Frost line depth in Mason County, IL

How deep the ground freezes in Mason County, IL

28 in. Dig to 29 in, just below the frost. Nearest NOAA station: Havana, 9.2 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