Frost line depth in Herkimer County, NY
How deep the ground freezes in Herkimer County, NY
53 in. Dig to 54 in, just below the frost. Nearest NOAA station: Old Forge, 11.6 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.