<SEC-DOCUMENT>0001125727-21-000005-index.html : 20210427
<SEC-HEADER>0001125727-21-000005.hdr.sgml : 20210427
<ACCEPTANCE-DATETIME>20210427172352
ACCESSION NUMBER:		0001125727-21-000005
CONFORMED SUBMISSION TYPE:	13F-HR
PUBLIC DOCUMENT COUNT:		2
CONFORMED PERIOD OF REPORT:	20210331
FILED AS OF DATE:		20210427
DATE AS OF CHANGE:		20210427
EFFECTIVENESS DATE:		20210427

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:		13F-HR
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	028-21151
		FILM NUMBER:		21860168

	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>13F-HR
<SEQUENCE>1
<FILENAME>primary_doc.xml
<TEXT>
Document 1 - file: primary_doc.html

Document 1 - RAW XML: primary_doc.xml

</DOCUMENT>
<DOCUMENT>
<TYPE>INFORMATION TABLE
<SEQUENCE>2
<FILENAME>information_table.xml
<DESCRIPTION>INFORMATION TABLE
<TEXT>
Document 2 - file: information_table.html

Document 2 - RAW XML: information_table.xml

</DOCUMENT>
</SEC-DOCUMENT>