Frost line depth in McKenzie County, ND
How deep the ground freezes in McKenzie County, ND
58 in. Dig to 58 in, just below the frost. Nearest NOAA station: Watford City, 6.8 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.