<SEC-DOCUMENT>0000842517-21-000200.txt : 20210903
<SEC-HEADER>0000842517-21-000200.hdr.sgml : 20210903
<ACCEPTANCE-DATETIME>20210903160304
ACCESSION NUMBER:		0000842517-21-000200
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20210901
FILED AS OF DATE:		20210903
DATE AS OF CHANGE:		20210903

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Varner Gregory V
		CENTRAL INDEX KEY:			0001652075

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-18415
		FILM NUMBER:		211236451

	MAIL ADDRESS:	
		STREET 1:		8439 N. BLAIR RD.
		CITY:			BRECKENRIDGE
		STATE:			MI
		ZIP:			48615

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			ISABELLA BANK Corp
		CENTRAL INDEX KEY:			0000842517
		STANDARD INDUSTRIAL CLASSIFICATION:	STATE COMMERCIAL BANKS [6022]
		IRS NUMBER:				382830092
		STATE OF INCORPORATION:			MI
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		401 NORTH MAIN STREET
		CITY:			MT PLEASANT
		STATE:			MI
		ZIP:			48858
		BUSINESS PHONE:		9897729471

	MAIL ADDRESS:	
		STREET 1:		401 NORTH MAIN STREET
		CITY:			MT PLEASANT
		STATE:			MI
		ZIP:			48858

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	ISABELLA BANK CORP
		DATE OF NAME CHANGE:	20080602

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	IBT BANCORP INC /MI/
		DATE OF NAME CHANGE:	19920703
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>wf-form4_163069935382188.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2021-09-01</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000842517</issuerCik>
        <issuerName>ISABELLA BANK Corp</issuerName>
        <issuerTradingSymbol>ISBA</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001652075</rptOwnerCik>
            <rptOwnerName>Varner Gregory V</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>8439 N. BLAIR RD.</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>BRECKENRIDGE</rptOwnerCity>
            <rptOwnerState>MI</rptOwnerState>
            <rptOwnerZipCode>48615</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>common</value>
            </securityTitle>
            <transactionDate>
                <value>2021-09-01</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>255</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>23</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>22151.4534</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Shares acquired with quarterly director fees pursuant to the Isabella Bank Corporation And Related Companies Deferred Compensation Plan For Directors.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Jennifer L. Gill, By Power of Attorney</signatureName>
        <signatureDate>2021-09-03</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
