<SEC-DOCUMENT>0000715579-23-000009.txt : 20230210
<SEC-HEADER>0000715579-23-000009.hdr.sgml : 20230210
<ACCEPTANCE-DATETIME>20230210140308
ACCESSION NUMBER:		0000715579-23-000009
CONFORMED SUBMISSION TYPE:	5
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20221231
FILED AS OF DATE:		20230210
DATE AS OF CHANGE:		20230210

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Seibel Douglas A
		CENTRAL INDEX KEY:			0001708277

	FILING VALUES:
		FORM TYPE:		5
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-35015
		FILM NUMBER:		23610382

	MAIL ADDRESS:	
		STREET 1:		348 FOXLEIGH DRIVE
		CITY:			HANOVER
		STATE:			PA
		ZIP:			17331

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>5
<SEQUENCE>1
<FILENAME>wf-form5_167605577356743.xml
<DESCRIPTION>FORM 5
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>5</documentType>

    <periodOfReport>2022-12-31</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <form3HoldingsReported>0</form3HoldingsReported>

    <form4TransactionsReported>0</form4TransactionsReported>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001708277</rptOwnerCik>
            <rptOwnerName>Seibel Douglas A</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>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>ACNB Corporation Common</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>10970.3031</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">The amount of securities beneficially owned includes 255.9970 aggregate shares of common stock acquired in 2022 through the automatic reinvestment of dividends, which are exempt from the reporting requirements of Section 16 of the Securities Exchange Act of 1934.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Douglas A. Seibel</signatureName>
        <signatureDate>2023-02-10</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
