<SEC-DOCUMENT>0000715579-22-000084.txt : 20220920
<SEC-HEADER>0000715579-22-000084.hdr.sgml : 20220920
<ACCEPTANCE-DATETIME>20220920151925
ACCESSION NUMBER:		0000715579-22-000084
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20220915
FILED AS OF DATE:		20220920
DATE AS OF CHANGE:		20220920

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Seibel Donald Arthur Jr
		CENTRAL INDEX KEY:			0001710898

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-35015
		FILM NUMBER:		221253352

	MAIL ADDRESS:	
		STREET 1:		1001 GREEN VALLEY ROAD
		CITY:			NEW WINDSOR
		STATE:			MD
		ZIP:			21776

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_166370155060443.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2022-09-15</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001710898</rptOwnerCik>
            <rptOwnerName>Seibel Donald Arthur Jr</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>16 LINCOLN SQUARE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>GETTYSBURG</rptOwnerCity>
            <rptOwnerState>PA</rptOwnerState>
            <rptOwnerZipCode>17325</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>ACNB Corporation Common</value>
            </securityTitle>
            <transactionDate>
                <value>2022-09-15</value>
            </transactionDate>
            <deemedExecutionDate>
                <value>2022-09-19</value>
                <footnoteId id="F1"/>
            </deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>175.7066</value>
                    <footnoteId id="F2"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>32.725</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>20783.4956</value>
                    <footnoteId id="F3"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>ACNB Corporation Common</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>11370.9979</value>
                    <footnoteId id="F4"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Trust</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </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">The shares represent stock received in lieu of director fees pursuant to a plan.</footnote>
        <footnote id="F3">The amount of securities beneficially owned includes 28.682353 shares of common stock purchased for the same Transaction Date of September 15, 2022, 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="F4">The amount of securities beneficially owned includes 89.630252 shares of common stock purchased for the same Transaction Date of September 15, 2022, 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>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Lynda L. Glass as POA for Donald Arthur Seibel, Jr.</signatureName>
        <signatureDate>2022-09-20</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
