Stonewall is located in eastern Gillespie County on the Pedernales River, in the Hill Country of central Texas.
U.S. Route 290 passes through the community, leading west 14 miles (23 km) to Fredericksburg, the Gillespie County seat, and east 15 miles (24 km) to Johnson City.
Stonewall is 63 miles (101 km) west of Austin and 71 miles (114 km) north of San Antonio.

According to the U.S. Census Bureau, the Stonewall CDP has a total area of 15.2 square miles (39.4 km²), of which 15.1 square miles (39.0 km²) are land and 0.2 square miles (0.4 km²), or 0.95%, are water.
The Pedernales River flows from west to east just north of the center of town.
Stonewall is located in eastern Gillespie County on the Pedernales River, in the Hill Country of central Texas. U.S. Route 290 passes through the community, leading west 14 miles (23 km) to Fredericksburg, the Gillespie County seat, and east 15 miles (24 km) to Johnson City. Stonewall is 63 miles (101 km) west of Austin and 71 miles (114 km) north of San Antonio.
According to the U.S. Census Bureau, the Stonewall CDP has a total area of 15.2 square miles (39.4 km²), of which 15.1 square miles (39.0 km²) are land and 0.2 square miles (0.4 km²), or 0.95%, are water. The Pedernales River flows from west to east just north of the center of town.
Stonewall, Texas