Garfield is located at (30.196097, -97.551480), 12 miles (19 km) southeast of downtown Austin.
According to the United States Census Bureau in 2000, the CDP has a total area of 13.9 square miles (35.9 km²), of which, 13.7 square miles (35.4 km²) of it is land and 0.2 square miles (0.5 km²) of it (1.44%) is water.