Rocky Mountain Bank Address: 108 E Railroad St, Plains, MT 59859 Phone: (406) 826-3662 Banks, Mortgages, Loans Other Businesses: First Security Bank at 510 W Railroad Ave, Plains, MT 59859 Valley Towing at 638 Upper Lynch Creek Rd, Plains, MT 59859 Valley Towing at 75 Clark Creek Loop, Plains, MT 59859 Mission Valley Hm Inspections at 510 W 4th St, Plains, MT 59859