Frost line depth in Traill County, ND
How deep the ground freezes in Traill County, ND
60 in. Dig to 60 in, just below the frost. Nearest NOAA station: Hillsboro 3 N, 4.6 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.