Hamilton Pool Preserve

Hamilton Creek spills over a limestone lip into a pool that sits inside what was once a cave - the dome collapsed thousands of years ago, leaving a half-shell of overhanging rock with ferns and stalactites on the underside and the pool below. It is one of the more photographed swimming holes in the country, which is the problem: the site is small, the access road is a country lane, and Travis County runs a strict reservation system with every vehicle requiring a booked slot, released in advance and gone quickly. Swimming is closed regularly for bacterial counts after rain, and it is possible to arrive with a reservation and not be allowed in the water.

The landscape

• A collapsed cave dome - overhanging rock above the pool.
• A waterfall - over the limestone lip.
• Ferns and stalactites - on the underside of the grotto.
• A strict reservation system - every vehicle, booked in advance.

When to go

April to October; reservations release on a schedule and go fast. Half a day.

Good to know

No reservation means no entry, without exception. Swimming closes for bacteria levels after rain, and you are not refunded. The trail down is steep and rocky. Rockfall has closed the grotto area at times.

Nearby

Pedernales Falls is south-west; Austin is east.

Key facts