Hamilton Pool Preserve is a historic swimming hole which was designated a preserve by the Travis County Commissioner's Court in 1990. Located 3/4 mile upstream from its confluence with the Pedernales River, Hamilton Creek spills out over limestone outcroppings to create a 50 foot waterfall as it plunges into the head of a steep box canyon. The waterfall never completely dries up, but in dry times it does slow to a trickle. However, the pool's water level stays pretty constant, even during periods of drought.

http://www.co.travis.tx.us/tnr/parks/hamilton_pool.asp

The 1990 film "Hot Spot" starring Jennifer Connely contains a scene shot here. The other actress bather is local Austin DJ, Debra Cole.