PILOT KNOB (TRAVIS COUNTY)
PILOT KNOB (Travis County). Pilot Knob is a small summit (at 30°10' N, 97°42' W) on U.S. Highway 183 seven miles south of Austin in Travis County. It stands at an elevation of 711 feet above sea level, rising 100 to 150 feet above the surrounding countryside. Pilot Knob, formed at the bottom of a shallow sea about 80 million years ago, is said to be the only example of an exposed submarine volcano in Texas. A historical marker about this physical feature has been placed at the intersection of U.S. Highway 183 and Farm Road 1625.