    <SEC-DOCUMENT>0000842517-21-000073-index.html : 20210326
    <SEC-HEADER>0000842517-21-000073.hdr.sgml : 20210326
    <ACCEPTANCE-DATETIME>20210326085755
    ACCESSION NUMBER:		0000842517-21-000073
    CONFORMED SUBMISSION TYPE:	DEF 14A
    PUBLIC DOCUMENT COUNT:		7
    CONFORMED PERIOD OF REPORT:	20210504
    FILED AS OF DATE:		20210326
    DATE AS OF CHANGE:		20210326

    FILER:

    	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

    	FILING VALUES:
    		FORM TYPE:		DEF 14A
    		SEC ACT:		1934 Act
    		SEC FILE NUMBER:	000-18415
    		FILM NUMBER:		21774887

    	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>DEF 14A
    <SEQUENCE>1
    <FILENAME>isba_2021xdef14a.htm
    <DESCRIPTION>DEF 14A
    <TEXT>
    Document 1 - file: isba_2021xdef14a.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>2
    <FILENAME>ibclogoa041a.jpg
    <DESCRIPTION>ISBA LOGO
    <TEXT>
    Document 2 - file: ibclogoa041a.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>3
    <FILENAME>debracampbella041a.jpg
    <DESCRIPTION>SIGNATURE
    <TEXT>
    Document 3 - file: debracampbella041a.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>4
    <FILENAME>proxycovervotea041a.jpg
    <DESCRIPTION>VOTING
    <TEXT>
    Document 4 - file: proxycovervotea041a.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>5
    <FILENAME>proxycard11.jpg
    <DESCRIPTION>PROXY CARD
    <TEXT>
    Document 5 - file: proxycard11.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>6
    <FILENAME>proxycard21.jpg
    <DESCRIPTION>PROXY CARD
    <TEXT>
    Document 6 - file: proxycard21.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>7
    <FILENAME>proxycard1.jpg
    <DESCRIPTION>PROXY CARD
    <TEXT>
    Document 7 - file: proxycard1.jpg

    </DOCUMENT>
    </SEC-DOCUMENT>