Hamilton Pool Preserve: reservations and swim status

Hamilton Pool Preserve is a collapsed grotto west of Austin where a waterfall feeds a green pool below overhanging rock walls, and getting in takes more paperwork than most swimming holes: Travis County requires a reservation every day of the year, on top of a separate entrance fee paid in cash at the gate. Even then, swimming isn't guaranteed. The county closes the water to swimmers whenever bacteria levels or falling-rock risk call for it, and posts the current status on the preserve's own page. It's a shared entry in our swimming holes in Texas guide and our waterfalls in Texas guide, since it functions as both.

No sourced coordinates are available yet for swimming holes — there is no government register for this category to map against (see methodology). Every spot is listed in the table below with directions in the text.

Fact box

Field	Detail
Coordinates	Approximate, 30.342°N, 98.127°W, Travis County, near Dripping Springs
Access type	Official, Travis County preserve; reservation required every day, swimming not guaranteed
Water source	Spring-fed pool below a collapsed grotto and waterfall
Depth	Deep enough for swimming when the water is open to visitors; exact depth hasn't been independently measured for this guide
Reservation fee	$12 per vehicle (up to 8 people), one vehicle per reservation, booked online by card
Entrance fee	$8 per adult (13 to 61), $3 senior (62 and up), free for kids 12 and under; cash only at the preserve
Swim status	Posted by Travis County Parks; water access is limited to part of the pool because of falling-rock risk and closes outright when bacteria tests run high, typically after rain
Legal status	Official, Travis County preserve
Season	Open year-round by reservation; swimming can close on short notice

Reservations and fees

Travis County requires a reservation to enter Hamilton Pool Preserve every day of the year, with no walk-ups. Booking online costs $12 per vehicle, covering up to 8 people, and each reservation covers a single vehicle or motorcycle. On arrival you pay a separate entrance fee of $8 per adult (13 to 61), $3 for seniors 62 and up, and nothing for kids 12 and under. The preserve takes cash only for that fee; credit and debit cards aren't accepted at the gate, so bring bills (Travis County Parks, Hamilton Pool Preserve). Popular weekend and holiday dates book out well in advance.

A reservation gets you into the preserve and lets you walk down to the pool, but it doesn't guarantee a swim. Travis County closes the water whenever bacteria testing comes back high, usually after heavy rain, and the trail and viewing area stay open while the water itself is off-limits. Even when swimming is allowed, the county keeps water access to a portion of the pool away from the overhanging cliff because of falling rock. Rain-driven bacteria closures have recurred through recent seasons and can run well beyond a single day (KXAN, Hamilton Pool: rain helps waterfall flow but brings bacteria problem).

The pool and waterfall

Hamilton Pool formed when the dome of an underground river collapsed thousands of years ago, leaving a half-canyon of overhanging limestone with ferns growing from the cliff face and a waterfall spilling into the green pool below. The falls is what puts Hamilton Pool first in our waterfalls in Texas coverage, and for many visitors it, not the swimming, is the reason to make the drive.

How this guide was researched

This page was compiled from Travis County Parks' official reservation and fee page for Hamilton Pool Preserve, KXAN's reporting on the preserve's recurring bacteria-related swim closures, the Texas Department of State Health Services and the CDC. We haven't visited this site ourselves. Reservation fees, entrance fees and swim status change, sometimes daily; verify current status before you go. Last checked September 2026.

Before you go

Check the preserve's page on the Travis County Parks site on the day of your visit, since that's where the county posts whether swimming is open. Don't assume the water is open just because you hold a reservation; bacteria and rockfall closures come with little notice, especially after rain. See our waterfall safety guide for footing and flash-flood basics that apply here too, since the trail down to the grotto crosses wet rock in places. Once you're at the water, our swimming hole safety guide covers depth checks and what an unguarded pool means in practice.

Booking well ahead matters more here than at most sites in our swimming holes finder: the daily reservation cap means popular dates, especially weekends, fill up before most people start planning.

When swimming is open, the state's standard freshwater precaution applies here as at any Texas swimming hole. Texas has the country's highest documented case count of Naegleria fowleri, a rare but usually fatal amoeba found in warm freshwater, and the Texas Department of State Health Services recommends holding your nose or using nose clips when jumping in (Texas DSHS, PAM FAQs; CDC, preventing Naegleria infection when swimming).

FAQ

Do you need a reservation for Hamilton Pool?

Yes, every day of the year. It's $12 per vehicle online, plus an $8 per-adult entrance fee ($3 senior, free 12 and under) paid in cash at the gate.

Can you always swim at Hamilton Pool?

No. A reservation gets you into the preserve, but the county closes water access on short notice when bacteria levels or rockfall risk require it, independent of your booking. Even when open, only part of the pool is available for swimming.

How do you check if swimming is open at Hamilton Pool?

Check the preserve's page on the Travis County Parks site before you go. The county posts the current swim status there, and conditions can change day to day, especially after rain.

Is Hamilton Pool a waterfall or a swimming hole?

Both. A waterfall feeds the pool inside a collapsed limestone grotto, which is why it appears in this locator's waterfalls and swimming-holes coverage.

We haven't visited these places ourselves, and every page says so rather than implying otherwise. Details are compiled from public land-manager, USGS and NOAA sources and cross-checked where possible; conditions, access rules and fees change without notice, so confirm with the managing agency before you go. Page last checked September 2026. Read our full methodology.