<SEC-DOCUMENT>0000860413-23-000125-index.html : 20230525
<SEC-HEADER>0000860413-23-000125.hdr.sgml : 20230525
<ACCEPTANCE-DATETIME>20230525170714
ACCESSION NUMBER:		0000860413-23-000125
CONFORMED SUBMISSION TYPE:	S-8
PUBLIC DOCUMENT COUNT:		5
FILED AS OF DATE:		20230525
DATE AS OF CHANGE:		20230525
EFFECTIVENESS DATE:		20230525

FILER:

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			FIRST INTERSTATE BANCSYSTEM INC
		CENTRAL INDEX KEY:			0000860413
		STANDARD INDUSTRIAL CLASSIFICATION:	STATE COMMERCIAL BANKS [6022]
		IRS NUMBER:				810331430
		STATE OF INCORPORATION:			MT
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		S-8
		SEC ACT:		1933 Act
		SEC FILE NUMBER:	333-272210
		FILM NUMBER:		23961909

	BUSINESS ADDRESS:	
		STREET 1:		P O BOX 30918
		STREET 2:		401 NO 31ST STREET
		CITY:			BILLINGS
		STATE:			MT
		ZIP:			59116-0918
		BUSINESS PHONE:		4062555300

	MAIL ADDRESS:	
		STREET 1:		P O BOX 30918
		STREET 2:		401 NO 31ST STREET
		CITY:			BILLINGS
		STATE:			MT
		ZIP:			59116-0918

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	FIRST INTERSTATE BANCSYSTEM OF MONTANA INC
		DATE OF NAME CHANGE:	19930615
</SEC-HEADER>
<DOCUMENT>
<TYPE>S-8
<SEQUENCE>1
<FILENAME>fibk-20230525xsx8.htm
<DESCRIPTION>S-8
<TEXT>
Document 1 - file: fibk-20230525xsx8.htm

</DOCUMENT>
<DOCUMENT>
<TYPE>EX-FILING FEES
<SEQUENCE>2
<FILENAME>fibk-20230525xex107_feetab.htm
<DESCRIPTION>EX-107 FILING FEES
<TEXT>
Document 2 - file: fibk-20230525xex107_feetab.htm

</DOCUMENT>
<DOCUMENT>
<TYPE>EX-5.1
<SEQUENCE>3
<FILENAME>fibk-20230525xex51polsinel.htm
<DESCRIPTION>EX-5.1
<TEXT>
Document 3 - file: fibk-20230525xex51polsinel.htm

</DOCUMENT>
<DOCUMENT>
<TYPE>EX-23.1
<SEQUENCE>4
<FILENAME>fibk-20230525xex231_consen.htm
<DESCRIPTION>EX-23.1
<TEXT>
Document 4 - file: fibk-20230525xex231_consen.htm

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

</DOCUMENT>
</SEC-DOCUMENT>