Frost line depth in La Salle County, TX
How deep the ground freezes in La Salle County, TX
no frost in a normal winter. Dig to 12 in, the 12 in code minimum. Nearest NOAA station: Cotulla La Salle Co Ap, 10.4 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.