Frost line depth in Lincoln County, NV
How deep the ground freezes in Lincoln County, NV
15 in. Dig to 15 in, just below the frost. Nearest NOAA station: Caliente, 18.5 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.