Mountain Plains Bank
| Status: | Inactive as of 04/01/1989 |
| Merger - Without Assistance | |
| Successor Bank: | The First Western Bank Sturgis |
| Headquarters: | Mountain Plains Bank 1400 North Avenue Spearfish, SD 57783 |
| Established: | 06/07/1983 |
| FDIC Insurance: | 06/07/1983 |
| FDIC Cert: | #24508 |
| Charter Class: | Commercial bank, state charter and Fed member, supervised by the Federal Reserve (FRB) |
| Total Assets: | $16,100,000 |
| Total Deposits: | $15,152,000 |
History
| 1983-06-07 | Institution established: Original name:Mountain Plains Bank | |
| 1989-04-01 | Merged into and subsequently operated as part of The First Western Bank Sturgis (26773) in STURGIS, SD | |
| 2008-02-20 | Changed institution class to INSURED COMMERCIAL OR SAVINGS BANKS, STATE, MEMBERS FRS | |
| 2009-09-26 | Acquired The First Western Bank Sturgis (26773) in STURGIS, SD | |
| 2009-09-26 | Acquired First Western Bank (488) in WALL, SD | |
| 2009-09-26 | Merged into and subsequently operated as part of First Interstate Bank (1105) in BILLINGS, MT | |
| 2014-10-18 | Acquired Mountain West Bank, National Association (33314) in HELENA, MT | |
| 2015-07-25 | Acquired United Bank (18772) in ABSAROKEE, MT | |
| 2016-08-13 | Acquired Flathead Bank of Bigfork, Montana (20382) in BIGFORK, MT | |
| 2017-08-12 | Acquired Bank of the Cascades (22407) in BEND, OR | |
| 2018-11-10 | Acquired Inland Northwest Bank (27601) in SPOKANE, WA | |
| 2019-04-08 | Acquired Community 1st Bank (58576) in POST FALLS, ID | |
| 2019-04-08 | Acquired Idaho Independent Bank (33845) in COEUR D ALENE, ID |