<SEC-DOCUMENT>0001140361-21-042096-index.html : 20211216
<SEC-HEADER>0001140361-21-042096.hdr.sgml : 20211216
<ACCEPTANCE-DATETIME>20211216172803
ACCESSION NUMBER:		0001140361-21-042096
CONFORMED SUBMISSION TYPE:	424B3
PUBLIC DOCUMENT COUNT:		14
FILED AS OF DATE:		20211216
DATE AS OF CHANGE:		20211216

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:		424B3
		SEC ACT:		1933 Act
		SEC FILE NUMBER:	333-260771
		FILM NUMBER:		211498628

	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>424B3
<SEQUENCE>1
<FILENAME>ny20001148x5_424b3.htm
<DESCRIPTION>424B3
<TEXT>
Document 1 - file: ny20001148x5_424b3.htm

</DOCUMENT>
<DOCUMENT>
<TYPE>GRAPHIC
<SEQUENCE>2
<FILENAME>header_pipersandler2.jpg
<TEXT>
Document 2 - file: header_pipersandler2.jpg

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

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

</DOCUMENT>
<DOCUMENT>
<TYPE>GRAPHIC
<SEQUENCE>5
<FILENAME>logo_firstinterstatebanx1.jpg
<TEXT>
Document 5 - file: logo_firstinterstatebanx1.jpg

</DOCUMENT>
<DOCUMENT>
<TYPE>GRAPHIC
<SEQUENCE>6
<FILENAME>logo_greatwesternbankx2.jpg
<TEXT>
Document 6 - file: logo_greatwesternbankx2.jpg

</DOCUMENT>
<DOCUMENT>
<TYPE>GRAPHIC
<SEQUENCE>7
<FILENAME>logo_keefe-bruyettewoods.jpg
<TEXT>
Document 7 - file: logo_keefe-bruyettewoods.jpg

</DOCUMENT>
<DOCUMENT>
<TYPE>GRAPHIC
<SEQUENCE>8
<FILENAME>sig_jamesbrannen.jpg
<TEXT>
Document 8 - file: sig_jamesbrannen.jpg

</DOCUMENT>
<DOCUMENT>
<TYPE>GRAPHIC
<SEQUENCE>9
<FILENAME>sig_keefe-bruyettewoods.jpg
<TEXT>
Document 9 - file: sig_keefe-bruyettewoods.jpg

</DOCUMENT>
<DOCUMENT>
<TYPE>GRAPHIC
<SEQUENCE>10
<FILENAME>sig_kevinriley.jpg
<TEXT>
Document 10 - file: sig_kevinriley.jpg

</DOCUMENT>
<DOCUMENT>
<TYPE>GRAPHIC
<SEQUENCE>11
<FILENAME>sig_kevinrileyx1.jpg
<TEXT>
Document 11 - file: sig_kevinrileyx1.jpg

</DOCUMENT>
<DOCUMENT>
<TYPE>GRAPHIC
<SEQUENCE>12
<FILENAME>sig_markborrecco.jpg
<TEXT>
Document 12 - file: sig_markborrecco.jpg

</DOCUMENT>
<DOCUMENT>
<TYPE>GRAPHIC
<SEQUENCE>13
<FILENAME>sig_markborreccox1.jpg
<TEXT>
Document 13 - file: sig_markborreccox1.jpg

</DOCUMENT>
<DOCUMENT>
<TYPE>GRAPHIC
<SEQUENCE>14
<FILENAME>sig_pipersandler2.jpg
<TEXT>
Document 14 - file: sig_pipersandler2.jpg

</DOCUMENT>
</SEC-DOCUMENT>