Filed pursuant to Rule 424(b)(5)
Registration No. 333-219876

The information in this preliminary prospectus supplement is not complete and may be changed. This preliminary prospectus supplement and the accompanying base prospectus are not an offer to sell these securities, and are not soliciting an offer to buy these securities, in any jurisdiction where the offer or sale is not permitted.

SUBJECT TO COMPLETION

PRELIMINARY PROSPECTUS SUPPLEMENT DATED MARCH 14, 2018

PROSPECTUS SUPPLEMENT

(To Prospectus Dated August 23, 2017)

RGC Resources, Inc.

Common Stock

Having an Aggregate Offering Price of $14,000,000

We are offering shares of our common stock having an aggregate offering price of $14,000,000.

Our common stock is listed on the NASDAQ Global Market and trades under the symbol “RGCO.” On March 13, 2018, the last reported sale price of our common stock on the NASDAQ Global Market was $24.82 per share.

Investing in our common stock involves certain risks. See “Risk Factors” beginning on page S-11 of this prospectus supplement. You should carefully consider the risks discussed therein before investing in shares of our common stock.

We have granted the underwriters a 30-day option to purchase up to an additional              shares of common stock from us at the public offering price less the underwriting discount. If the underwriters exercise this option in full, the total public offering price will be $16,100,000, the total underwriting discounts will be $             and the total proceeds to us, before expenses, will be $            .

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus supplement or the accompanying base prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

The underwriters expect to deliver the shares on or about                 , 2018.

Joint Book-Running Managers

Co-Manager

Seaport Global Securities

The date of this prospectus supplement is March    , 2018.

TABLE OF CONTENTS

Prospectus Supplement

Base Prospectus

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ABOUT THIS PROSPECTUS SUPPLEMENT

This document is in two parts. The first part is the prospectus supplement, which describes the specific terms of this common stock offering and certain other matters relating to us and our financial condition. The second part, the accompanying base prospectus, gives more general information about us and our common stock. Generally, when we refer to the prospectus, we are referring to both parts of this document combined. To the extent the description of our common stock in the prospectus supplement differs from the description of our common stock in the accompanying base prospectus, you should only rely on the information in the prospectus supplement.

You should rely only on the information contained in or incorporated by reference into this document or included in other offering materials filed by us with the Securities and Exchange Commission (the “SEC”) which relate specifically to this common stock offering. Neither we nor the underwriters have authorized anyone to provide you with different information. If anyone provides you with different or additional information, you should not rely on it. You should not assume that the information contained in or incorporated by reference into this document or included in other offering materials filed by us with the SEC is accurate as of any date other than the date of this document, the date of the document in which the incorporated information appears or the date of any such offering materials, as applicable. Our business, financial condition, results of operations and prospectus may have changed since the relevant date.

This document may only be used where it is legal to sell these securities.

When we use the terms “we,” “our,” “us,” “RGC Resources” or the “Company” in the prospectus supplement or the accompanying base prospectus, we are referring to RGC Resources, Inc, a Virginia corporation, and its consolidated subsidiaries.

We have filed a registration statement on Form S-3 with the SEC. This prospectus supplement and the accompanying base prospectus are a part of the registration statement and do not contain all of the information in the registration statement. Whenever a reference is made in this prospectus supplement or the accompanying base prospectus to any of our contracts or other documents, please be aware that such reference is not necessarily complete and that you should refer to the exhibits that are a part of the registration statement for a copy of the contract or other document. You may review a copy of the registration statement at the SEC’s Public Reference Room in Washington, D.C., as well as through the SEC’s Internet website.

WHERE YOU CAN FIND MORE INFORMATION

We file annual, quarterly and current reports, proxy statements and other information with the SEC. Our file number with the SEC is 000-26591. Our SEC filings are available to the public over the Internet on the SEC’s website at http://www.sec.gov. You may also read and copy any document we file with the SEC at the SEC’s Public Reference Room located at 100 F. Street, N.E., Washington, D.C. 20549. Please call the SEC at 1-800-SEC-0330 for further information on the public reference room.

INCORPORATION OF CERTAIN INFORMATION BY REFERENCE

The SEC allows us to “incorporate by reference” into this prospectus supplement the information we file with the SEC. This means that we can disclose important information to you by referring you to those documents without restating that information in this document. The information incorporated by reference into this prospectus supplement is considered to be part of this prospectus supplement. Information included in this prospectus supplement updates and supersedes information incorporated by reference from documents that we filed with the SEC prior to the date of this prospectus supplement, while information that we file with the SEC in

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the future will automatically update and supersede the information in this prospectus supplement or incorporated by reference into this prospectus supplement from documents filed prior to the date of this prospectus supplement.

We incorporate by reference into this prospectus supplement the documents listed below and any future filings made by us with the SEC under Sections 13(a), 13(c), 14 or 15(d) of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), other than any such documents or filings, or portions thereof, that are deemed to be furnished to, but not filed with, the SEC, until such time as all of the securities covered by this prospectus supplement have been sold:

Upon written or oral request, we will provide a copy of any of the documents incorporated herein by reference, without charge, to each person, including any beneficial owner, to whom this prospectus supplement is delivered. Requests for any such documents should be directed to:

RGC Resources, Inc.

519 Kimball Avenue, N.E.

Roanoke, Virginia 24016

Attn: Investor Relations

(540) 777-3853

CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS

This prospectus supplement and the accompanying base prospectus include and incorporate by reference forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995 and the corresponding safe harbors provided by Section 27A of the Securities Act of 1933, as amended (the “Securities Act”), and Section 21E of the Exchange Act. In many cases, forward-looking statements are identifiable by the use of words such as “anticipate,” “estimate,” “forecast,” “project,” “target,” “expect,” “believe,” “should,” “could,” “plan,” “may,” “intend,” “goal,” “potential,” “continue” or other similar words. Examples include statements as to, among other things, our future business plans and expansion opportunities, including expansion opportunities related to the Mountain Valley Pipeline Project (as defined in “Summary” beginning on page S-6 below) and the general potential for customer growth, the implementation or completion and benefits of certain business strategies or projects, including estimated completion dates for the construction of the Mountain Valley Pipeline Project and the anticipated benefits of the Mountain Valley Pipeline Project, future capital expenditures, including with respect to our investment in the Mountain Valley Pipeline Project, anticipated financial performance, the receipt and timing of any regulatory approvals, technological developments and the demand for and price of natural gas. These and other forward-looking statements, by their nature, involve estimates, projections, forecasts and uncertainties that could cause actual results or outcomes to differ materially from those expressed in the applicable statement. Factors that could cause actual results or outcomes to differ from those stated include, but are not limited to, those discussed or referred to in “Risk Factors” beginning on page S-11, as well as the following:

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In light of these risks and uncertainties, readers are cautioned not to place undue reliance on our forward-looking statements. Any forward-looking statement speaks only as of the date on which it is made, and we undertake no obligation to publicly update or revise any forward-looking statement, whether as a result of new information, future events or circumstances or otherwise.

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RISK FACTORS

Investing in our common stock involves certain risks, including the risks referred to or described below that relate to our business and to this offering and our common stock. You should carefully consider and evaluate these risks, as well as the other information included and incorporated by reference into this prospectus supplement and the accompanying base prospectus and any other offering materials filed by us with the SEC, before deciding whether to invest in our common stock. Our business, results of operations or financial condition could be adversely affected by any of these risks or by additional risks and uncertainties not currently known to us or that we currently consider immaterial.

Risks Related to Our Business

Our business is influenced by many factors that are difficult to predict, involve uncertainties that may materially affect actual results and are often beyond our control. We have identified a number of these factors under the heading “Risk Factors” in our Annual Report on Form 10-K for the year ended September 30, 2017, which is incorporated by reference into this prospectus supplement.

Risks Related to this Offering and Our Common Stock

The market price of our common stock may be adversely affected by the issuance and sale of our common stock, including pursuant to this offering.

Except as described under the heading “Underwriting,” we are not restricted from issuing additional shares of our common stock or other equity-related securities. We cannot predict the effect that issuances or sales of our common stock, including pursuant to this offering, may have on the market price for our common stock. The issuance and sale of substantial amounts of common stock or other equity-related securities, including issuances and sales pursuant to this offering, could adversely affect the market price of our common stock.

The market price of our common stock may fluctuate significantly, and shares of our common stock may trade at prices below the price at which you purchased them.

The market price of our common stock following this offering may fluctuate significantly as a result of many factors, including, but not limited to:

These factors, as well as those referred to under “Risks Related to Our Business” above and other factors relating to the market as a whole or our industry, may adversely affect the market price of our common stock, regardless, in some instances, of our actual operating performance. As a result, shares of our common stock may trade at prices significantly below the price paid by you in this offering.

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We may not be able to continue paying regular dividend payments, which could adversely affect the market price of our common stock.

Our ability to continue paying regular dividends is based on many factors, including the success of our operations, the demand for our services, our regulatory environment and the cost recovery and other rate mechanisms available to us and our liquidity needs. Many of these factors are beyond our control and a change in these factors could adversely impact our ability to continue paying regular dividends. In addition, the terms of any additional debt we incur in the future could, in certain circumstances, limit our ability to pay dividends. A failure by us to continue paying regular dividends could adversely affect the market price of our common stock.

Our common stock is an equity security and is subordinate to our existing and any future indebtedness.

Shares of our common stock are equity interests and, as such, rank junior to all of our current indebtedness as well as any indebtedness incurred by us in the future. Accordingly, in the event of a bankruptcy, liquidation or other similar proceeding, your rights as a holder of our common stock will be subordinate to the rights of the holders of our indebtedness and any other non-equity claims against us.

Certain provisions in our organizational documents and in Virginia law may deter or delay an acquisition of us.

Certain provisions of the Virginia Stock Corporation Act and our articles of incorporation and bylaws may deter or delay certain transactions that our shareholders may otherwise consider to be in their best interest, including transactions that might result in our shareholders receiving a premium for their shares. See “Description of Common Stock” below and the material referred to therein for more information.

Non-U.S. holders may be subject to U.S. federal income tax on gain realized on the sale or disposition of shares of our common stock.

Because of our overall mix of assets, we can give no assurance that we are not or will not become a “U.S. real property holding corporation” (which we refer to as “USRPHC”) for U.S. federal income tax purposes. If we are or if we become a USRPHC, so long as our common stock is regularly traded on an established securities market, such stock will be treated as a U.S. real property interest only with respect to a non-U.S. holder that actually or constructively owns more than 5 percent of our common stock at any time during the shorter of the five-year period preceding the disposition or the holder’s holding period for such stock. No assurance can be given that our common stock will remain regularly traded in the future. If our stock is treated as a U.S. real property interest, a non-U.S. holder would be subject to U.S. federal income tax on the gain realized on a disposition of such stock at the graduated U.S. federal income tax rates applicable to U.S. persons, generally would be required to file a U.S. federal income tax return, and, if the common stock was not then regularly traded, and certain other conditions were met, the purchaser would be required to withhold 15% of the sales proceeds.

Non-U.S. holders should consult their tax advisors concerning the consequences of disposing of shares of our common stock.

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USE OF PROCEEDS

We intend to use the net proceeds from this offering for general corporate purposes and to fund capital expenditures, such as the projects discussed under “Summary – RGC Resources – Utility Plant Investment” and a portion of our required contributions to Mountain Valley Pipeline, LLC. In the interim, we may use the net proceeds, or a portion thereof, to repay certain debt, including amounts outstanding under Roanoke Gas’ revolving line of credit with Wells Fargo Bank, N.A. As of March 9, 2018, approximately $10.3 million was outstanding under this facility at a weighted average interest rate of 2.75%. The facility matures on March 31, 2019. Amounts borrowed under the facility were used to fund working capital and provide bridge financing for our infrastructure replacement program.

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CAPITALIZATION

The table below sets forth our capitalization as of December 31, 2017 on an actual basis and as adjusted to give effect to the sale of common stock in this offering and our intended use of the net proceeds from this offering. The table below assumes no exercise by the underwriters of their option to purchase additional shares. You should read this table in conjunction with our audited financial statements contained in our Annual Report on Form 10-K for the year ended September 30, 2017, as well as the unaudited information presented in our most recent Quarterly Report on Form 10-Q filed for the quarter ended December 31, 2017, each of which is incorporated by reference into this prospectus supplement. See “Where You Can Find More Information,” “Incorporation of Certain Information by Reference,” and “Use of Proceeds” elsewhere in this prospectus supplement.

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DESCRIPTION OF COMMON STOCK

For a description of our common stock, see “Description of Common Stock” in the accompanying base prospectus as well as the description of our common stock contained in Exhibit 99.1 to our Current Report on Form 8-K filed on August 10, 2017, which is incorporated into this prospectus supplement by reference.

COMMON STOCK PRICE RANGE AND DIVIDENDS

Our common stock is listed on the NASDAQ Global Market and trades under the symbol “RGCO.” The following table sets forth the high and low sales prices of our common stock on the NASDAQ Global Market and the cash dividends per share declared on our common stock during the periods indicated. All amounts for periods preceding March 1, 2017 have been adjusted to give retroactive effect to the three-for-two split of our common stock effective as of that date.

The last reported sales price of our common stock on the NASDAQ Global Market on March 13, 2018 was $24.82 per share. As of March 2, 2018, we had 7,275,392 shares of common stock outstanding, and there were approximately 1,158 holders of record of our common stock.

Dividends are paid on our common stock as declared by our Board of Directors. We have paid cash dividends on our common stock for 296 consecutive quarters. It is the intention of our Board of Directors to continue to pay cash dividends on our common stock on a quarterly basis. However, the payment of future dividends, and the amount of any such dividends, is dependent on a number of factors, including the success of our operations, the demand for our services, our regulatory environment and the cost recovery and other rate mechanisms available to us and our liquidity needs. A number of these factors are outside of our control. In addition, the covenants in any future debt facilities entered into by us may, in certain circumstances, limit our ability to pay dividends. We therefore cannot assure you that we will pay dividends in the future or that we will maintain or raise the level of dividends paid in the future. Our Board of Directors may elect at any time and for an indefinite duration to cease paying dividends on our common stock.

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CERTAIN UNITED STATES FEDERAL INCOME TAX CONSIDERATIONS FOR NON-U.S. HOLDERS

The following discussion summarizes certain United States (“U.S.”) federal income tax considerations relevant to “Non-U.S. holders” (defined below) relating to the acquisition, ownership and disposition of shares of our common stock. This summary is based upon the provisions of the Internal Revenue Code of 1986, as amended (the “Code”), Treasury regulations promulgated thereunder, administrative rulings and judicial decisions, all as in effect on the date hereof. These authorities may be changed, possibly retroactively, so as to result in U.S. federal income tax consequences different from those set forth below. We have not sought any ruling from the Internal Revenue Service (“IRS”) with respect to the statements made and the conclusions reached in the following summary, and there can be no assurance that the IRS will agree with such statements and conclusions.

For purposes of this summary, a “Non-U.S. Holder” means a beneficial owner of shares of our common stock that is not a U.S. person or a partnership for U.S. federal income tax purposes. A U.S. person means a beneficial owner of shares of our common stock that is for U.S. federal income tax purposes:

This summary does not address the tax considerations arising under the laws of any non U.S., state, or local jurisdiction or under U.S. federal gift and estate tax laws. In addition, this discussion does not address tax considerations applicable to a non-U.S. holder’s particular circumstances or to non-U.S. holders that may be subject to special tax rules, including, without limitation:

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If a partnership or entity classified as a partnership for U.S. federal income tax purposes holds our common stock, the tax treatment of a partner or such partnership generally will depend on the status of the partner and upon the activities of the partnership. Accordingly, partnerships that hold our common stock, and partners in such partnerships, should consult their tax advisors.

You are urged to consult your tax advisor with respect to the application of the U.S. federal income tax laws to your particular situation, as well as any tax consequences of the purchase, ownership and disposition of our common stock arising under the U.S. federal estate or gift tax rules or under the laws of any state, local, non-U.S. or other taxing jurisdiction or under any applicable tax treaty.

Distributions

In general, if we make a distribution to a Non-U.S. Holder with respect to our common stock, it will constitute a dividend for U.S. federal income tax purposes to the extent paid out of our current or accumulated earnings and profits as determined under the Code. If the amount of a distribution exceeds our current and accumulated earnings and profits, such excess will first be treated as a tax-free return of capital to the extent of the Non-U.S. Holder’s adjusted tax basis in our common shares. Thereafter, any remaining excess will be treated as capital gain from the sale or exchange of our common stock as described below in “Sale or Other Disposition of Common Stock.”

Dividends paid to a Non-U.S. Holder that are not effectively connected with the Non-U.S. Holder’s conduct of a trade or business within the United States will generally be subject to U.S. federal withholding tax at a rate of 30% of the gross amount of the dividends or such lower rate as specified by an applicable income tax treaty. In order to obtain the benefit of a reduced rate of withholding, a Non-U.S. Holder is generally required to provide to the applicable withholding agent an IRS Form W-8BEN or IRS Form W-8BEN-E (or a suitable substitute form) properly certifying such Non-U.S. Holder’s eligibility for the reduced rate. Non-U.S. Holders that do not timely provide the applicable withholding agent with the required certification, but that qualify for a reduced withholding rate, may obtain a refund of any excess amounts withheld by timely filing an appropriate claim for a refund with the IRS. Non-U.S. Holders should consult their tax advisors regarding their entitlement to benefits under an applicable income tax treaty and the timing and manner of claiming the benefits.

Dividends that are effectively connected with a Non-U.S. Holder’s conduct of a trade or business in the United States and, if an applicable income tax treaty so requires, are attributable to a permanent establishment maintained by the Non-U.S. Holder in the United States, are taxed on a net-income basis at the regular graduated rates and in the manner applicable to United States persons. The Non-U.S. Holder is generally required to provide to the applicable withholding agent a properly executed IRS Form W-8ECI (or a suitable substitute form) in order to claim an exemption from, or reduction in, U.S. federal withholding tax. In addition, a “branch profits tax” may be imposed at a 30% rate (or a reduced rate under an applicable income tax treaty) on any effectively connected dividends received by a foreign corporation for the taxable year, as adjusted for certain items.

Sale or Other Taxable Disposition of Common Stock

Subject to the discussion below regarding backup withholding and the Foreign Account Tax Compliance Act, a Non-U.S. Holder generally will not be subject to U.S. federal income or withholding tax with respect to gain, if any, recognized on the sale or other taxable disposition of shares of our common stock unless (i) the gain is effectively connected with the conduct by such Non-U.S. Holder of a trade or business within the United States, and, if certain tax treaties apply, is attributable to a permanent establishment or fixed base within the United States, (ii) in the case of an individual, such Non-U.S. Holder is present in the United States for 183 or more days in the taxable year of the disposition and certain other conditions are satisfied, or (iii) our common

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stock constitutes a U.S. real property interest by reason of our status as a USRPHC under the Foreign Investment in Real Property Tax Act (“FIRPTA”) for U.S. federal income tax purposes.

In the case described in (i) above, gain or loss recognized on the disposition of shares of our common stock generally will be subject to U.S. federal income taxation in the same manner as if such gain or loss were recognized by a U.S. person, and, in the case of a Non-U.S. Holder that is a foreign corporation, may also be subject to the branch profits tax at a rate of 30% (or a lower applicable treaty branch profits tax rate).

In the case described in (ii) above, the Non-U.S. Holder will be subject to a 30% tax on any capital gain recognized on the disposition of shares of our common stock (after being offset by certain U.S.-source capital losses).

In the case described in (iii) above, a corporation is a USRPHC if the fair market value of its U.S. real property interests equals or exceeds 50 percent of the sum of the fair market value of its worldwide real property interests and its other assets used or held for use in a trade or business (all as determined for U.S. federal income tax purposes). Given the lack of clear guidance in this area, there can be no assurances that we are not or will not become a USRPHC. If, however, we were a USRPHC during the shorter of the five-year period preceding the disposition or the Non-U.S. Holder’s holding period, Non-U.S. Holders owning (actually or constructively) more than 5 percent of our common stock will be subject to different tax consequences and should consult their own tax advisers. U.S. federal income tax will not apply to gain realized on the sale or disposition of our common stock by a Non-U.S. Holder that owns (actually or constructively at any time during the shorter of the five-year period preceding the date of disposition or the Non-U.S. Holder’s holding period) 5 percent or less of our common stock so long as our common stock is “regularly traded on an established securities market” (such as the New York Stock Exchange) as defined under applicable Treasury regulations. No assurance can be given that our common stock will continue to satisfy this requirement in the future.

If gain on the sale or other taxable disposition of the common stock were subject to taxation under FIRPTA, a Non-U.S. Holder generally would be subject to U.S. federal income tax on the gain realized on a disposition of the common stock at the graduated U.S. federal income tax rates applicable to U.S. persons, generally would be required to file a U.S. federal income tax return, and, if the common stock was not then regularly traded, and certain other conditions were met, the purchaser would be required to withhold 15% of the sales proceeds.

Information Reporting and Backup Withholding

Generally, we must report to the IRS and to Non-U.S. Holders the amount of dividends and non-dividend distributions paid to Non-U.S. Holders and the amount of tax, if any, withheld with respect to those payments. Copies of these information returns may also be made available under the provisions of a specific tax treaty or other agreement to the tax authorities of the country in which the Non-U.S. Holder resides.

Unless the Non-U.S. Holder complies with certification procedures to establish that it is not a United States person, information returns may be filed with the IRS in connection with the proceeds from a sale or other disposition, and the Non-U.S. Holder may be subject to backup withholding (currently at a rate of 28%) on dividends paid on our common stock or on the proceeds from a sale or other disposition of shares of our common stock. The certification procedures required to claim a reduction or exemption from withholding tax on payments described above under “Distributions” will satisfy the certification requirements necessary to avoid backup withholding as well. Backup withholding is not an additional tax. Any amounts withheld under the backup withholding rules may be allowed as a refund or a credit against a Non-U.S. Holder’s U.S. federal income tax liability provided the required information is timely furnished to the IRS.

Foreign Account Tax Compliance Act

Under the Foreign Account Tax Compliance Act (“FATCA”) and additional guidance issued by the IRS, a U.S. federal withholding tax of 30% generally applies to certain payments (including dividends paid on our

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common stock and, after December 31, 2018, will include gross proceeds from the sale or other disposition of shares of our common stock) paid to (i) a foreign financial institution (as a beneficial owner or as an intermediary), unless such institution enters into an agreement with the U.S. government to collect and provide to the U.S. tax authorities substantial information regarding U.S. account holders of such institution (which would include certain equity and debt holders of such institution, as well as certain account holders that are foreign entities with U.S. owners), or (ii) a foreign entity that is not a financial institution (as a beneficial owner or as an intermediary), unless such entity provides the withholding agent with a certification identifying the substantial U.S. owners of the entity, which generally includes any U.S. person who directly or indirectly owns more than 10% of the entity. Non-U.S. Holders are encouraged to consult with their tax advisors regarding the possible implications of the FATCA withholding rules on their investment in our common stock. If a dividend payment is both subject to withholding under FATCA and subject to the withholding tax discussed above under “Distributions,” the withholding under FATCA may be credited against, and therefore reduce, such other withholding tax.

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UNDERWRITING

We have entered into an underwriting agreement, dated March     , 2018, with BB&T Capital Markets, a division of BB&T Securities, LLC, and Janney Montgomery Scott LLC, acting as representatives of the underwriters named below, with respect to the shares of our common stock being offered pursuant to this prospectus supplement. Subject to the terms and conditions contained in the underwriting agreement, we have agreed to sell and the underwriters have agreed to purchase from us the number of shares of common stock set forth opposite their names in the following table:

Option to Purchase Additional Shares

The underwriters have an option to purchase up to an additional              shares of our common stock. They may exercise this option for 30 days from the date of the underwriting agreement. If any shares are purchased pursuant to this option, the underwriters will severally purchase shares in approximately the same proportion as set forth in the table above, and the underwriters will offer the additional shares on the same terms as those on which the shares listed in the table above are being offered.

We are obligated to sell these additional shares of our common stock to the underwriters to the extent that their option to purchase such additional shares is exercised. The underwriters may exercise this option solely for the purpose of covering over-allotments, if any, made in connection with the offering of the common stock offered by this prospectus supplement.

Discounts and Commissions

The underwriters propose to initially offer the shares of our common stock subject to this prospectus supplement at the public offering price on the cover page of this prospectus supplement and to certain dealers at that price less a concession not in excess of $             per share. After the public offering, the underwriters may change the public offering price and concessions to dealers.

The following table summarizes the compensation to be paid to the underwriters in connection with this offering. The information assumes either no exercise or full exercise by the underwriters of their option to purchase additional shares.

We estimate that the expenses payable by us in connection with this offering, other than the underwriting discounts referred to above, will be approximately $205,000.

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Lock-up Arrangements

We have agreed that, for a period of 90 days after the date of this prospectus supplement, we will not (i) offer, pledge, sell, contract to sell, sell any option or contract to purchase, purchase any option or contract to sell, grant any option, right or warrant to purchase, or otherwise transfer or dispose of, directly or indirectly, or file with the SEC a registration statement under the Securities Act relating to, any shares of our common stock or any securities convertible into or exercisable or exchangeable for our common stock, or publicly disclose the intention to make any offer, sale, pledge, disposition or filing, or (ii) enter into any swap or other agreement that transfers, in whole or in part, any of the economic consequences of ownership of shares of our common stock or any such other securities, whether any such transaction described in clause (i) or (ii) above is to be settled by delivery of Stock or such other securities, in cash or otherwise, without the prior written consent of BB&T Capital Markets, a division of BB&T Securities, LLC, and Janney Montgomery Scott LLC, other than (A) the shares to be sold in this offering, (B) any shares of our common stock granted pursuant to our stock-based compensation plans, (C) any shares of our common stock issued upon the exercise of options granted under our stock-based compensation plans or (D) any shares of our common stock sold under our dividend reinvestment and stock purchase plan.

Our directors and executive officers have entered into lock-up agreements prior to the commencement of this offering pursuant to which each of these persons, for a period of 90 days after the date of this prospectus supplement, may not, without the prior written consent of BB&T Capital Markets, a division of BB&T Securities, LLC, and Janney Montgomery Scott LLC (1) offer, pledge, sell, contract to sell, sell any option or contract to purchase, purchase any option or contract to sell, grant any option, right or warrant to purchase, or otherwise transfer or dispose of, directly or indirectly, any shares of our common stock or any securities convertible into or exercisable or exchangeable for our common stock (including without limitation, our common stock or such other securities which may be deemed to be beneficially owned by such person in accordance with the rules and regulations of the SEC and securities which may be issued upon exercise of a stock option or warrant), or publicly disclose the intention to make any offer, sale, pledge or disposition, (2) enter into any swap or other agreement that transfers, in whole or in part, any of the economic consequences of ownership of our common stock or such other securities, whether any such transaction described in clause (1) or (2) above is to be settled by delivery of our common stock or such other securities, in cash or otherwise or (3) make any demand for or exercise any right with respect to the registration of any shares of our common stock or any security convertible into or exercisable or exchangeable for our common stock, in each case other than (A) transfers of shares of our common stock as a bona fide gift or gifts; (B) dispositions to any trust for the direct or indirect benefit of such person and/or a member of the immediate family of such person; (C) the transfer or intestate succession to the legal representative or a member of the immediate family of such person; (D) transfers pursuant to domestic relations or court orders; or (E) in connection with any sale or surrender to us of any options or shares of our common stock underlying options or any restricted stock in order to pay the exercise price or taxes associated with the exercise of options or vesting of restricted stock; provided that in the case of any transfer or distribution pursuant to clause (A), (B), (C) or (D), each transferee, donee or distributee shall execute and deliver to BB&T Capital Markets, a division of BB&T Securities, LLC, and Janney Montgomery Scott LLC a lock-up letter in the form of this paragraph; and provided, further, that in the case of any transfer or distribution pursuant to clause (C), no filing by any party (donor, donee, transferor or transferee) under the Exchange Act or other public announcement shall be required or shall be made voluntarily in connection with such transfer or distribution (other than a filing on a Form 5 made after the expiration of the Restricted Period referred to above); and provided, further, that any required filing or announcement (including a filing on Form 4) by such person or us relating to a sale pursuant to clause (A), (B) or (D) shall briefly note the applicable circumstances that cause such clause to apply and explain that the filing or announcement relates solely to transfers falling within the category described in the relevant clause (including, in the case of a Form 4 filing, indicating the appropriate transaction code(s) required by General Instruction 8 to Form 4). For purposes of this paragraph in respect of a director or executive officer, “immediate family” shall mean such person and any relationship by blood, marriage or adoption, not remote than first cousin.

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Indemnity

We have agreed to indemnify the underwriters against certain liabilities, including liabilities under the Securities Act of 1933, as amended, arising out of this prospectus supplement, the accompanying base prospectus and certain other materials in connection with this offering.

Other Relationships with the Underwriters

The underwriters are full service financial institutions engaged in various activities, which may include securities trading, commercial and investment banking, financial advisory, investment management, principal investment, hedging, financing and brokerage activities. The underwriters and their respective affiliates may, from time to time, engage in transactions with and perform services for us in the ordinary course of their business for which they may receive customary fees and reimbursement of expenses. In particular, in November 2016, Roanoke Gas entered into an unsecured note with an affiliate of BB&T Capital Markets, a division of BB&T Securities, LLC, in the principal amount of $7,000,000. In addition, in December 2015, Midstream entered into an unsecured promissory note with the same affiliate of BB&T Capital Markets, a division of BB&T Securities, LLC, in the principal amount of $10,000,000. None of the net proceeds of this offering will be used to repay amounts due to such affiliate under either promissory note. In the ordinary course of their various business activities, the underwriters and their respective affiliates may make or hold a broad array of investments and actively trade debt and equity securities (or related derivative securities) and financial instruments (which may include bank loans and/or credit default swaps) for their own account and for the accounts of their customers and may at any time hold long and short positions in such securities and instruments. Such investments and securities activities may involve securities and/or instruments of ours or our affiliates. The underwriters and their affiliates may also make investment recommendations and/or publish or express independent research views in respect of such securities or financial instruments and may hold, or recommend to clients that they acquire, long and/or short positions in such securities and instruments.

Stabilization

The underwriters may engage in over-allotment transactions, stabilizing transactions and syndicate covering transactions in accordance with Regulation M under the Exchange Act.

These stabilizing transactions and syndicate covering transactions may cause the price of our common stock to be higher than the price that might otherwise exist in the open market. These transactions may be effected on the NASDAQ Global Market or otherwise. Neither we nor any of the underwriters make any representation that the underwriters will engage in any of the transactions described above. If commenced, the underwriters may discontinue these transactions at any time without notice. Neither we nor any of the underwriters make any representation or prediction as to the effect that the transactions described above, if commenced, may have on the market price of shares of our common stock.

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LEGAL MATTERS

The validity of the issuance of the common stock offered under this prospectus supplement and accompanying base prospectus and certain other legal matters with respect to this offering will be passed upon for us by McGuireWoods LLP, Richmond, Virginia. Certain legal matters will be passed upon for the underwriters by Troutman Sanders LLP, Richmond, Virginia.

EXPERTS

The consolidated financial statements incorporated in this prospectus supplement by reference from our Annual Report on Form 10-K for the year ended September 30, 2017 and the effectiveness of our internal control over financial reporting have been audited by Brown, Edwards & Company, L.L.P., an independent registered public accounting firm as stated in their reports, which are incorporated herein by reference. Such consolidated financial statements have been so incorporated in reliance upon the reports of such firm given upon their authority as experts in accounting and auditing.

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PROSPECTUS

$50,000,000

RGC Resources, Inc.

Common Stock

We may from time to time offer and sell shares of our common stock in one or more offerings with an aggregate offering amount of up to $50,000,000.

This prospectus provides you with a general description of the common stock that we may offer and a general description of the manner in which we may offer it. Each time we offer shares of our common stock, we will provide a prospectus supplement that contains more specific information about the terms of the offering, including the specific manner in which those shares will be sold and the prices at which those shares will be sold. We may also supplement, update or amend in the prospectus supplement any of the information contained in this prospectus. You should read this prospectus and the applicable prospectus supplement carefully before investing in shares of our common stock.

We may sell shares of our common stock through agents or underwriters and dealers that we select. If agents, underwriters or dealers are used to sell shares, we will name them and describe their compensation in the applicable prospectus supplement.

Our common stock trades on the NASDAQ Global Market under the symbol RGCO. On August 9, 2017, the last reported sales price of our common stock, as reported on the NASDAQ Global Market, was $26.65 per share.

Investing in our common stock involves certain risks. See “Risk Factors” on page 4 of this prospectus and in any accompanying prospectus supplement, as well as the Risk Factors section of our most recent Annual Report on Form 10-K and the other reports we file with the Securities and Exchange Commission. You should carefully consider these factors before investing in shares of our common stock.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or passed upon the adequacy or accuracy of this prospectus. Any representation to the contrary is a criminal offense.

The date of this prospectus is August 23, 2017.

TABLE OF CONTENTS

ABOUT THIS PROSPECTUS

This prospectus is part of a registration statement that we filed with the Securities and Exchange Commission (the “SEC”) utilizing a “shelf” registration process. Under this shelf registration process, we may from time to time sell shares of our common stock in one or more offerings with an aggregate offering amount of up to $50,000,000.

This prospectus provides you with a general description of the shares of common stock we may offer and a general description of the manner in which we may offer it. Each time we offer shares of common stock under this prospectus, we will provide one or more prospectus supplements that will contain specific information about the terms of the offering. The prospectus supplement may also supplement, update or amend information contained in this prospectus. You should carefully read both this prospectus and the accompanying prospectus supplement, together with the additional information incorporated into this prospectus, as described below, and the information described under the heading “Where You Can Find More Information,” before investing in our common stock.

You should rely only on the information contained in or incorporated by reference into this prospectus and any prospectus supplement. We have not authorized anyone to provide you with additional or different information. If anyone provides you with additional or different information, you should not rely on it. This prospectus and any prospectus supplement are not an offer to sell, nor a solicitation of an offer to buy, shares of our common stock in any jurisdiction where the offer or sale is not permitted. You should not assume that the information contained in this prospectus is accurate as of any date other than the date on the front cover of this prospectus, or that the information contained in any document incorporated by reference is accurate as of any date other than the date of the document incorporated by reference, regardless of the time of delivery of this prospectus or any sale of shares of our common stock. Our business, financial condition, results of operations and prospects may have changed since the relevant date.

We will not use this prospectus to offer and sell securities unless it is accompanied by a prospectus supplement that more fully described the terms of the applicable offering.

When we use the terms “we,” “our,” “us,” RGC Resources” or the “Company” in this prospectus, we are referring to RGC Resources, Inc, a Virginia corporation, and its consolidated subsidiaries.

WHERE YOU CAN FIND MORE INFORMATION

We file annual, quarterly and current reports, proxy statements and other information with the SEC. Our file number with the SEC is 000-26591. Our SEC filings are available to the public over the Internet on the SEC’s

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website at http://www.sec.gov. You may also read and copy any document we file with the SEC at the SEC’s Public Reference Room located at 100 F. Street, N.E., Washington, D.C. 20549. Please call the SEC at 1-800-SEC-0330 for further information on the public reference room.

INCORPORATION OF CERTAIN INFORMATION BY REFERENCE

The SEC allows us to “incorporate by reference” into this prospectus the information we file with the SEC. This means that we can disclose important information to you by referring you to those documents without restating that information in this document. The information incorporated by reference into this prospectus is considered to be part of this prospectus, and information we file with the SEC pursuant to Section 13(a), 13(c), 14 or 15(d) of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), after the date of this prospectus and prior to the termination of this offering, will automatically update and supersede the information contained in this prospectus and the documents listed below. We incorporate by reference into this prospectus the documents listed below, except to the extent information in those documents differs from information contained in this prospectus, and any future filings made by us with the SEC under Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act, including exhibits (however, unless specifically indicated, we do not incorporate by reference, whether listed below or filed in the future, current reports furnished under Item 2.02 or Item 7.01 of Form 8-K or related exhibits furnished pursuant to Item 9.01 of Form 8-K):

Upon written or oral request, we will provide a copy of any of the documents incorporated herein by reference, without charge, to each person, including any beneficial owner, to whom this prospectus is delivered. Requests for any such documents should be directed to:

RGC Resources, Inc.

519 Kimball Avenue, N.E.

Roanoke, Virginia 24016

Attn: Investor Relations

(540) 777-3853

CAUTIONARY STATEMENT CONCERNING FORWARD-LOOKING INFORMATION

This prospectus may contain or incorporate by reference forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995 and the safe harbor provided by Section 27A of the Securities Act of 1933, as amended (the “Securities Act”), and Section 21E of the Exchange Act. Examples include statements relating to such matters as anticipated financial performance, business prospects, technological developments, new products, research and development activities and similar matters. These statements, by their nature, involve estimates, projections, forecasts and uncertainties that could cause actual results or outcomes to differ materially from those expressed in the forward-looking statements. Factors that could cause actual results or outcomes to differ from those in the forward-looking statements may accompany the statements themselves. In addition, generally applicable factors that could cause actual results or outcomes to differ from those in the forward-looking statements are, or will be, discussed under the heading “Risk Factors” and elsewhere in the reports we file with the SEC, which are incorporated herein by reference, and in any prospectus supplement.

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Any forward-looking statement speaks only as of the date on which it is made, and we undertake no obligation to update any forward-looking statement to reflect events or circumstances occurring or arising after the date on which it is made.

ABOUT RGC RESOURCES, INC.

RGC Resources, incorporated in Virginia in July 1998, is an energy services company primarily engaged in the regulated sale and distribution of natural gas to residential, commercial and industrial customers in Roanoke, Virginia and the surrounding localities through its Roanoke Gas Company subsidiary. RGC Resources’ utility operations are regulated by the Virginia State Corporation Commission, which oversees the terms, conditions and rates to be charged to the Company’s natural gas customers. RGC Resources also holds, through RGC Midstream, LLC, a 1% interest in Mountain Valley Pipeline, LLC, which was created in August 2014 for the purpose of constructing a natural gas pipeline connecting an existing natural gas gathering and transmission system in northern West Virginia to another interstate pipeline in south central Virginia.

The Company’s principal executive offices are located at 519 Kimball Avenue, N.E., Roanoke, Virginia 24016 and its telephone number is (540) 777-4427. The Company maintains a website at www.rgcresources.com. Information contained on or accessible through the Company’s website is not a part of this prospectus.

RISK FACTORS

Investing in our common stock involves certain risks. Our business is influenced by many factors that are difficult to predict, involve uncertainties that may materially affect actual results and are often beyond our control. We have identified a number of these factors under the heading “Risk Factors” in our Annual Report on Form 10-K for the year ended September 30, 2016, which are incorporated by reference in this prospectus, as well as in other information included or incorporated by reference in this prospectus and any prospectus supplement. Before making an investment decision, you should carefully consider these risks as well as the other information we include or incorporate by reference in this prospectus and any prospectus supplement.    

USE OF PROCEEDS

Unless otherwise indicated in the applicable prospectus supplement, we intend to use the net proceeds from the sale of the shares of our common stock offered under this prospectus to finance capital expenditures and for other general corporate purposes, including to reduce indebtedness or to fund future acquisitions of, or investments in, assets or businesses.

DESCRIPTION OF COMMON STOCK

The following summary of the terms of our common stock may not be complete and is subject to, and qualified in its entirety by reference to, the description of our common stock contained in Exhibit 99.1 to our Current Report on Form 8-K filed August 10, 2017, which is incorporated herein by reference, and the provisions of our articles of incorporation and bylaws. You should read this summary together with the description of our common stock noted above, as well as our articles of incorporation and bylaws, before investing in our common stock.

Authorized and Outstanding Shares

We are authorized to issue 10,000,000 shares of common stock, par value $5.00. As of July 31, 2017, approximately 7,232,482 shares of our common stock were issued and outstanding. All of our issued and outstanding shares of common stock are fully paid and non-assessable.

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Voting Rights

All voting rights are vested in the holders of our common stock. Each share of common stock is entitled to one vote in the election of directors and on other matters requiring shareholder action. Holders of our common stock are not entitled to cumulative voting rights. The voting rights of holders of our common stock may be impacted by any voting rights associated with shares of preferred stock issued by us in the future.

Dividend Rights

Holders of our common stock are entitled to receive such dividends as may be declared by our Board of Directors. Dividends may be paid in cash, stock or other form. The dividend rights of holders of our common stock may be subject to the dividend rights of holders of any shares of preferred stock issued by us in the future.

Liquidation Rights

In the event of any voluntary or involuntary liquidation, dissolution or winding up of our affairs, holders of our common stock will be entitled to share equally in all assets remaining after the payment of all liabilities and any accrued dividends and liquidation preferences on any shares of preferred stock then outstanding.

Other Rights

Holders of our common stock have no preemptive, subscription, redemption or conversion rights, and there are no sinking fund provisions applicable to our common stock.

Listing

Our common stock is traded on the NASDAQ Global Market under the symbol RGCO.

Transfer Agent and Registrar

Broadridge Corporate Issuer Solutions, Inc. serves as transfer agent and registrar for our common stock.

Preferred Stock

We are authorized to issue 5,000,000 shares of preferred stock, no par value. As of July 31, 2017, no shares of preferred stock were outstanding. Our board of directors has full authority, without shareholder approval, to establish and issue one or more series of preferred stock. Our board of directors also has full authority to determine the number of shares of each series and the rights (which may include voting rights), preferences and limitations of each series. All series of our preferred stock would rank, with respect to dividends and liquidation rights, senior to our common stock. The future issuance of any series of preferred stock could also adversely impact the voting rights of the holders of our common stock.

Anti-Takeover Matters

Certain provisions of the Virginia Stock Corporation Act and our articles of incorporation and bylaws may have an anti-takeover effect and deter certain transactions that our shareholders may otherwise consider to be in their best interest, including transactions that might result in our shareholders receiving a premium for their shares. The provisions of this type in our articles and bylaws include, among others, those relating to our classified board of directors, our “blank check” preferred stock and the requirements for calling a special meeting of shareholders. The provisions of this type in the Virginia Stock Corporation Act include, among others, the affiliated transactions statute and the control share acquisitions statute. For a more detailed discussion of these provisions, see the description of our common stock contained in Exhibit 99.1 to our Current Report on Form 8-K filed August 10, 2017, which is incorporated herein by reference.

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PLAN OF DISTRIBUTION

We may sell the shares of common stock offered under this prospectus in any of the ways described below or in any way set forth in an applicable prospectus supplement:

The distribution of shares of common stock offered under this prospectus may be effected from time to time in one or more transactions:

We will set forth in a prospectus supplement the terms of a particular offering of shares of our common stock under this prospectus, including:

Underwriters may offer and sell the shares of common stock offered under this prospectus from time to time in one or more transactions, including negotiated transactions, at a fixed public offering price, or at varying prices determined at the time of sale. The obligations of the underwriters to purchase the shares will be subject to the conditions set forth in an underwriting agreement between us and the underwriters. If underwriters are used in the sale of any shares, the shares will be acquired by the underwriters for their own account and may be resold from time to time in one or more transactions described above. The shares may be either offered to the public through underwriting syndicates represented by managing underwriters, or directly by underwriters. Generally, the underwriters’ obligations to purchase the shares will be subject to certain conditions precedent. The underwriters will be obligated to purchase all of the shares if they purchase any of the shares. We may use underwriters with whom we have a material relationship. We will describe in the prospectus supplement or a free writing prospectus, naming the underwriter, the nature of any such relationship.

Any offering price and any discounts or concessions allowed or re-allowed or paid to dealers may be changed from time to time.

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We may from time to time engage a firm to act as our agent for one or more offerings of our shares of common stock under this prospectus. We sometimes refer to this agent as our “offering agent.” If we reach agreement with an offering agent with respect to a specific offering, including the number of shares and any minimum price below which sales may not be made, then the offering agent will try to sell such shares on the agreed terms. The offering agent could make sales in privately negotiated transactions or using any other method permitted by law, including sales deemed to be through an “at the market” offering as defined in Rule 415 under the Securities Act, including sales made directly on the NASDAQ Global Market, or sales made to or through a market maker other than on an exchange. The offering agent will be deemed to be an “underwriter” within the meaning of the Securities Act with respect to any sales effected through an “at the market” offering.

Agents, underwriters and other third parties described above may be entitled to indemnification by us against certain civil liabilities, including liabilities under the Securities Act, or to contribution from us with respect to payments that the agents, underwriters, or other third parties may be required to make in respect of these civil liabilities. Agents, underwriters, and such other third parties may be customers of, engage in transactions with or perform services for us in the ordinary course of business.

Certain underwriters may use the prospectus and any accompanying prospectus supplement for offers and sales related to market-making transactions in the shares of common stock. These underwriters may act as principal or agent in these transactions, and the sales will be made at prices related to prevailing market prices at the time of sale.

Certain persons participating in an offering may engage in overallotment, stabilizing transactions, short covering transactions and penalty bids in accordance with rules and regulations under the Exchange Act. Overallotment involves sales in excess of the offering size, which create a short position. Stabilizing transactions permit bids to purchase the underlying security so long as the stabilizing bids do not exceed a specified maximum. Short covering transactions involve purchases of shares in the open market after the distribution is completed to cover short positions. Penalty bids permit the underwriters to reclaim a selling concession from a dealer when the shares originally sold by the dealer are purchased in a short covering transaction to cover short positions. Those activities may cause the price of the shares to be higher than it would otherwise be. If commenced, the underwriters may discontinue any of the activities at any time.

To the extent permitted by and in accordance with Regulation M under the Exchange Act, any underwriters who are qualified market makers on the NASDAQ Global Market may engage in passive market making transactions in our shares of common stock on the NASDAQ Global Market during the business day prior to the pricing of an offering, before the commencement of offers or sales. Passive market makers must comply with applicable volume and price limitations and must be identified as passive market makers. In general, a passive market maker must display its bid at a price not in excess of the highest independent bid for such security; if all independent bids are lowered below the passive market maker’s bid, however, the passive market maker’s bid must then be lowered when certain purchase limits are exceeded.

We also may sell any of the shares of common stock offered under this prospectus through other agents designated by us from time to time. We will name any agent involved in the offer or sale of the shares and will list any commissions payable by us to these agents in the applicable prospectus supplement. These agents will be acting on a best efforts basis to solicit purchases for the period of their appointment, unless stated otherwise in the applicable prospectus supplements.

EXPERTS

The consolidated financial statements incorporated in this prospectus by reference from our Annual Report on Form 10-K for the year ended September 30, 2016 and the effectiveness of our internal control over financial reporting have been audited by Brown, Edwards & Company, L.L.P., an independent registered public

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accounting firm as stated in their reports, which are incorporated herein by reference. Such consolidated financial statements have been so incorporated in reliance upon the reports of such firm given upon their authority as experts in accounting and auditing.

LEGAL MATTERS

The validity of the shares of common stock offered under this prospectus will be passed upon for us by McGuireWoods, LLP, Richmond, Virginia. Underwriters, dealers or agents, if any, who we identify in a prospectus supplement may have their own counsel pass upon certain legal matters in connection with the shares of common stock offered under this prospectus.

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RGC Resources, Inc.

Common Stock

Having an Aggregate Offering Price of $14,000,000

PROSPECTUS SUPPLEMENT

Joint Book-Running Managers

Co-Manager

Seaport Global Securities