Hot Springs State Park Bath House - Free soaking · donation encouraged in Thermopolis, WY (2026)
Geodesic dome encloses ADA-accessible indoor and outdoor pools fed by the world’s largest mineral hot spring, complete with boardwalks over rainbow terraces.
Hot Springs State Park in Thermopolis, Wyoming is home to what claims to be the world's largest mineral hot spring (3.6 million gallons per day from Big Spring, at 127°F) — and the State Bath House inside the park offers free 20-minute soaks in indoor and outdoor pools fed by that source. It's a deliberate Wyoming legacy: the state acquired the springs from the Shoshone and Arapaho tribes in 1896 with a treaty stipulation that they remain free to the public forever. The bath house is ADA-accessible, geodesic-domed, and surrounded by terraces of mineral-deposited travertine in vivid orange, green, and white.
What to expect
Drive to the park (free entry), walk to the State Bath House. Sign in at the desk, change in the locker rooms, and you have 20 minutes in the indoor pool, the outdoor pool, or both. Sessions are timed and enforced. After your soak, walk the boardwalks across the rainbow travertine terraces and visit the bison herd that lives in the park. Two private water parks (Star Plunge and Hellie's TePee Pools) sit adjacent and offer paid waterslide experiences.
Temperature
104°-110°F
Pools
2 soaking pools
Best season
Year-round
Reservations
Walk-up friendly
Dog policy
No pets at pools
Family policy
Family windows available
Safety notes
- Each soak is limited to 20 minutes—plan for multiple rotations if you want more time.
- The outdoor deck can be icy in winter; wear sandals with grip.
Amenities & etiquette
FAQ
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