Frost line depth in Pembina County, ND
How deep the ground freezes in Pembina County, ND
74 in. Dig to 74 in, just below the frost. Nearest NOAA station: Cavalier 7nw, 9.7 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.