Frost line depth in Prince George's County, MD

How deep the ground freezes in Prince George's County, MD

16 in. Dig to 17 in, just below the frost. Nearest NOAA station: Upper Marlboro 3 Nnw, 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.