Frost line depth in Logan County, OH
How deep the ground freezes in Logan County, OH
30 in. Dig to 30 in, just below the frost. Nearest NOAA station: Bellefontaine, 2.4 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.