<SEC-DOCUMENT>0001104659-23-064777-index.html : 20230526
<SEC-HEADER>0001104659-23-064777.hdr.sgml : 20230526
<ACCEPTANCE-DATETIME>20230525173519
ACCESSION NUMBER:		0001104659-23-064777
CONFORMED SUBMISSION TYPE:	S-3ASR
PUBLIC DOCUMENT COUNT:		9
FILED AS OF DATE:		20230526
DATE AS OF CHANGE:		20230525
EFFECTIVENESS DATE:		20230526

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-3ASR
		SEC ACT:		1933 Act
		SEC FILE NUMBER:	333-272215
		FILM NUMBER:		23962187

	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-3ASR
<SEQUENCE>1
<FILENAME>tm233533-1_s3asr.htm
<DESCRIPTION>S-3ASR
<TEXT>
Document 1 - file: tm233533-1_s3asr.htm

</DOCUMENT>
<DOCUMENT>
<TYPE>EX-4.4
<SEQUENCE>2
<FILENAME>tm233533d2_ex4-4.htm
<DESCRIPTION>EXHIBIT 4.4
<TEXT>
Document 2 - file: tm233533d2_ex4-4.htm

</DOCUMENT>
<DOCUMENT>
<TYPE>EX-4.5
<SEQUENCE>3
<FILENAME>tm233533d2_ex4-5.htm
<DESCRIPTION>EXHIBIT 4.5
<TEXT>
Document 3 - file: tm233533d2_ex4-5.htm

</DOCUMENT>
<DOCUMENT>
<TYPE>EX-5.1
<SEQUENCE>4
<FILENAME>tm233533d2_ex5-1.htm
<DESCRIPTION>EXHIBIT 5.1
<TEXT>
Document 4 - file: tm233533d2_ex5-1.htm

</DOCUMENT>
<DOCUMENT>
<TYPE>EX-23.1
<SEQUENCE>5
<FILENAME>tm233533d2_ex23-1.htm
<DESCRIPTION>EXHIBIT 23.1
<TEXT>
Document 5 - file: tm233533d2_ex23-1.htm

</DOCUMENT>
<DOCUMENT>
<TYPE>EX-FILING FEES
<SEQUENCE>6
<FILENAME>tm233533d2_ex-filingfees.htm
<DESCRIPTION>EX-FILING FEES
<TEXT>
Document 6 - file: tm233533d2_ex-filingfees.htm

</DOCUMENT>
<DOCUMENT>
<TYPE>GRAPHIC
<SEQUENCE>7
<FILENAME>lg_firstinterstatebanc-4clr.jpg
<DESCRIPTION>GRAPHIC
<TEXT>
Document 7 - file: lg_firstinterstatebanc-4clr.jpg

</DOCUMENT>
<DOCUMENT>
<TYPE>GRAPHIC
<SEQUENCE>8
<FILENAME>tm233533d2_ex5-1img001.jpg
<DESCRIPTION>GRAPHIC
<TEXT>
Document 8 - file: tm233533d2_ex5-1img001.jpg

</DOCUMENT>
<DOCUMENT>
<TYPE>GRAPHIC
<SEQUENCE>9
<FILENAME>tm233533d2_ex5-1img002.jpg
<DESCRIPTION>GRAPHIC
<TEXT>
Document 9 - file: tm233533d2_ex5-1img002.jpg

</DOCUMENT>
</SEC-DOCUMENT>