    <SEC-DOCUMENT>0000860413-25-000047-index.html : 20250408
    <SEC-HEADER>0000860413-25-000047.hdr.sgml : 20250408
    <ACCEPTANCE-DATETIME>20250408160828
    ACCESSION NUMBER:		0000860413-25-000047
    CONFORMED SUBMISSION TYPE:	ARS
    PUBLIC DOCUMENT COUNT:		1
    CONFORMED PERIOD OF REPORT:	20241231
    FILED AS OF DATE:		20250408
    DATE AS OF CHANGE:		20250408
    EFFECTIVENESS DATE:		20250408

    FILER:

    	COMPANY DATA:
    		COMPANY CONFORMED NAME:			FIRST INTERSTATE BANCSYSTEM INC
    		CENTRAL INDEX KEY:			0000860413
    		STANDARD INDUSTRIAL CLASSIFICATION:	STATE COMMERCIAL BANKS [6022]
    		ORGANIZATION NAME:           	02 Finance
    		EIN:				810331430
    		STATE OF INCORPORATION:			DE
    		FISCAL YEAR END:			1231

    	FILING VALUES:
    		FORM TYPE:		ARS
    		SEC ACT:		1934 Act
    		SEC FILE NUMBER:	001-34653
    		FILM NUMBER:		25822022

    	BUSINESS ADDRESS:
    		STREET 1:		401 NO 31ST STREET
    		CITY:			BILLINGS
    		STATE:			MT
    		ZIP:			59101
    		BUSINESS PHONE:		4062555311

    	MAIL ADDRESS:
    		STREET 1:		401 NO 31ST STREET
    		CITY:			BILLINGS
    		STATE:			MT
    		ZIP:			59101

    	FORMER COMPANY:
    		FORMER CONFORMED NAME:	FIRST INTERSTATE BANCSYSTEM OF MONTANA INC
    		DATE OF NAME CHANGE:	19930615
    </SEC-HEADER>
    <DOCUMENT>
    <TYPE>ARS
    <SEQUENCE>1
    <FILENAME>fibk_2024xars.pdf
    <DESCRIPTION>ARS
    <TEXT>
    Document 1 - file: fibk_2024xars.pdf

    </DOCUMENT>
    </SEC-DOCUMENT>