<SEC-DOCUMENT>0001628280-26-038011.txt : 20260526
<SEC-HEADER>0001628280-26-038011.hdr.sgml : 20260526
<ACCEPTANCE-DATETIME>20260526140037
ACCESSION NUMBER:		0001628280-26-038011
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20260526
FILED AS OF DATE:		20260526
DATE AS OF CHANGE:		20260526

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Kelley Scott L
		CENTRAL INDEX KEY:			0001549663
		ORGANIZATION NAME:           	

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-35015
		FILM NUMBER:		261018455

	MAIL ADDRESS:	
		STREET 1:		2068 ROSEWOOD LANE
		CITY:			YORK
		STATE:			PA
		ZIP:			17403

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			ACNB CORP
		CENTRAL INDEX KEY:			0000715579
		STANDARD INDUSTRIAL CLASSIFICATION:	STATE COMMERCIAL BANKS [6022]
		ORGANIZATION NAME:           	02 Finance
		EIN:				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>wk-form4_1779818435.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0609</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2026-05-26</periodOfReport>

    <notSubjectToSection16>1</notSubjectToSection16>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001549663</rptOwnerCik>
            <rptOwnerName>Kelley Scott L</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerNonUSAddressFlag>false</rptOwnerNonUSAddressFlag>
            <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>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>ACNB Corporation Common</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>27999.6123</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">This Form 4 is filed voluntarily to report that the Reporting Person ceased to be a director of the Issuer due to retirement from the board of directors on May 5, 2026, and is therefore no longer subject to Section 16 reporting requirements with respect to the Issuer.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Kevin J. Hayes as POA for Scott L. Kelley</signatureName>
        <signatureDate>2026-05-26</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
