Frost line depth in Ontonagon County, MI

How deep the ground freezes in Ontonagon County, MI

48 in. Dig to 49 in, just below the frost. Nearest NOAA station: Ontonagon 6 Se, 3.3 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.

Code depth · Snow