<SEC-DOCUMENT>0000715579-23-000030.txt : 20230321
<SEC-HEADER>0000715579-23-000030.hdr.sgml : 20230321
<ACCEPTANCE-DATETIME>20230321144312
ACCESSION NUMBER:		0000715579-23-000030
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20230315
FILED AS OF DATE:		20230321
DATE AS OF CHANGE:		20230321

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Stone Thomas R
		CENTRAL INDEX KEY:			0001708297

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-35015
		FILM NUMBER:		23749286

	MAIL ADDRESS:	
		STREET 1:		2701 PRIMROSE LANE E
		CITY:			YORK
		STATE:			PA
		ZIP:			17402

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			ACNB CORP
		CENTRAL INDEX KEY:			0000715579
		STANDARD INDUSTRIAL CLASSIFICATION:	STATE COMMERCIAL BANKS [6022]
		IRS NUMBER:				232233457
		STATE OF INCORPORATION:			PA
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		16 LINCOLN SQUARE
		STREET 2:		P O BOX 3129
		CITY:			GETTYSBURG
		STATE:			PA
		ZIP:			17325
		BUSINESS PHONE:		7173343161

	MAIL ADDRESS:	
		STREET 1:		P O BOX 3129
		STREET 2:		16 LINCOLN SQUARE
		CITY:			GETTYSBURG
		STATE:			PA
		ZIP:			17325
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>wf-form4_167942418198417.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0407</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2023-03-15</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000715579</issuerCik>
        <issuerName>ACNB CORP</issuerName>
        <issuerTradingSymbol>ACNB</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001708297</rptOwnerCik>
            <rptOwnerName>Stone Thomas R</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>16 LINCOLN SQUARE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>GETTYSBURG</rptOwnerCity>
            <rptOwnerState>PA</rptOwnerState>
            <rptOwnerZipCode>17325</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>1</isOther>
            <officerTitle></officerTitle>
            <otherText>ACNB Bank EVP</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>ACNB Corporation Common</value>
            </securityTitle>
            <transactionDate>
                <value>2023-03-15</value>
            </transactionDate>
            <deemedExecutionDate>
                <value>2023-03-17</value>
                <footnoteId id="F1"/>
            </deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>42.0323</value>
                    <footnoteId id="F2"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>31.915</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>6917.6031</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>ACNB Corporation Common</value>
            </securityTitle>
            <transactionDate>
                <value>2023-03-15</value>
            </transactionDate>
            <deemedExecutionDate>
                <value>2023-03-17</value>
                <footnoteId id="F1"/>
            </deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>3070.6564</value>
                    <footnoteId id="F3"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>31.915</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>10037.8819</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>ACNB Corporation Common</value>
            </securityTitle>
            <transactionDate>
                <value>2023-03-15</value>
            </transactionDate>
            <deemedExecutionDate>
                <value>2023-03-17</value>
                <footnoteId id="F1"/>
            </deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>F</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>283.953</value>
                    <footnoteId id="F4"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>31.915</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>9753.9289</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">The date of execution was determined in accordance with SEC Rule 16a-3(g)(2) and (g)(4).</footnote>
        <footnote id="F2">This amount includes shares of common stock purchased for the same transaction date through the automatic reinvestment of dividends under the ACNB Corporation Dividend Reinvestment and Stock Purchase Plan, which are exempt from the reporting requirements of Section 16 of the Securities Exchange Act of 1934.</footnote>
        <footnote id="F3">One-third (1/3) of this Variable Equity Award, granted in the form of restricted stock under the ACNB Bank Variable Compensation Plan and pursuant to the ACNB Corporation 2018 Omnibus Stock Incentive Plan, is 100% vested as of the Grant Date of March 15, 2023, with the next one-third (1/3) 100% vested as of January 1, 2024, and the final one-third (1/3) 100% vested as of January 1, 2025.</footnote>
        <footnote id="F4">This amount is in payment of the tax liability, by withholding of securities, on the first one-third (1/3) vested as of the Grant Date of March 15, 2023, in accordance with SEC Rule 16b-3.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Thomas R. Stone</signatureName>
        <signatureDate>2023-03-20</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
