Frost line depth in Broadwater County, MT
How deep the ground freezes in Broadwater County, MT
40 in. Dig to 40 in, just below the frost. Nearest NOAA station: Townsend 3se, 3 mi.
Your building department sets the legal frost line depth (IRC Table R301.2(1)); footings must go below it (R403.1.4.1). Call them before you dig.