Wyoming Lets You Soak in a Hot Spring for Free. Here’s How the Thermopolis State Bath House Works

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In Thermopolis, Wyoming, you can soak in mineral hot springs water without paying a cent. The Thermopolis State Bath House in Hot Springs State Park offers free soaks of about 20 minutes in indoor and outdoor pools. You walk in, sign in at the desk, change in the locker rooms, and soak. The tradition of free public access traces back to an 1896 treaty with the Shoshone and Arapaho tribes.

According to the Thermopolis visitor bureau, the Shoshone and Arapaho gave Wyoming the hot springs in an 1896 treaty, with the provision that the waters remain accessible to the public. The state honors that with the free bath house. The park’s Big Spring is promoted as one of the largest mineral hot springs in the world, sending millions of gallons of hot water a day over colorful terraces toward the Bighorn River.

It is one of the best travel deals in the Mountain West. Here is how the bath house works and how to make the most of a visit.

How the Thermopolis State Bath House works

The bath house is run by the state of Wyoming inside Hot Springs State Park, which has free entry. It is open year-round, though hours vary by season and day. The basic process is simple:

• Walk in. No reservation is needed, and soaking is walk-up.
• Sign in at the front desk. Staff track how long each visitor soaks.
• Change in the locker rooms. Bring your own swimsuit and towel. Some items may be available to rent.
• Soak for your time slot. Soaks are timed, typically around 20 minutes, and the limit is enforced.
• Rotate between pools. You can use the indoor pool, the outdoor pool, or both during your session.

The water is kept at a temperature similar to a hot tub, and the time limit exists partly for safety, since mineral hot water at that temperature can make some people lightheaded if they stay in too long.

Donations are encouraged, though not required. Check current hours with Wyoming State Parks before you go, as they may change.

Tips for your soak

• Bring sandals with grip. Pool decks can be slippery, and the outdoor deck can be icy in winter.
• Remove jewelry. Minerals in the water can tarnish some metals, especially silver.
• Drink water. Hot water can dehydrate you.
• Plan for the time limit. If you want more soaking time, ask staff about policies for returning later.
• Shower afterward. The water has a mineral smell that some people notice on their skin and hair.

Why soaking is free

The free bath house comes from a promise made more than a century ago. The hot springs at Thermopolis were long used and valued by Native American tribes, who believed the waters had healing power. In 1896, the Eastern Shoshone and Northern Arapaho, whose reservation lands included the springs, agreed to cede the hot springs area to the United States, which then transferred it to Wyoming.

According to the visitor bureau, the agreement included a provision that the waters remain accessible to the general public. The free state bath house fulfills that promise. Each summer, Thermopolis commemorates the treaty with the Gift of the Waters Pageant, held in the state park.

The Big Spring and the terraces

Hot Springs State Park’s main sight, apart from the bath house, is the Big Spring and the mineral terraces it has built. Water flows from the spring at a high temperature and runs across the ground toward the Bighorn River. As it cools, minerals precipitate out, creating terraces of travertine in shades of orange, yellow, white, and green from minerals and heat-loving microbes.

Boardwalks lead visitors over and around the terraces, with views of steam rising off the water, especially on cold mornings. A swinging suspension bridge over the Bighorn River offers a good view of the terraces and the river.

The water is very hot at the source. Stay on boardwalks and do not touch the water outside the designated soaking areas.

Other things to do in Hot Springs State Park

The park offers more than soaking:

• Bison herd: The park maintains a small herd of bison, which you can often see from a scenic loop drive.
• Swinging bridge: A pedestrian suspension bridge over the Bighorn River.
• Walking paths: Trails and boardwalks around the terraces and river.
• Picnic areas: Grassy spaces for a picnic in warmer months.
• Private pools: Commercial hot springs facilities in the park, with water slides and larger pools, charge their own admission.

Thermopolis beyond the park

Thermopolis is a small town in central Wyoming, and it makes a good stop for a night or two. Other attractions include:

• Wyoming Dinosaur Center: A museum with dinosaur skeletons and fossils, plus seasonal dig sites where visitors can watch or participate in excavations.
• Wind River Canyon: A dramatic canyon just south of town, where U.S. 20 follows the Wind River through towering rock walls. The canyon exposes rock layers spanning hundreds of millions of years of geologic history.
• Hot Springs County Museum: Local history, including ranching, Native American heritage, and the town’s development.
• Downtown Thermopolis: Small restaurants, shops, and historic buildings.

When to visit

The bath house is open year-round, and each season offers something different:

• Winter: Soaking in hot water while snow falls on the outdoor pool is a memorable experience. Steam rises thick off the terraces on cold days. Roads can be snowy, so check conditions.
• Spring and fall: Mild weather and fewer visitors.
• Summer: The busiest season, with the Gift of the Waters Pageant and full hours at nearby attractions.

Weekdays and early mornings tend to be quieter at the bath house.

Getting there

Thermopolis is in Hot Springs County in central Wyoming. It is about 130 miles from Casper, roughly 85 miles from Cody, and about 130 miles from Yellowstone’s East Entrance. The town sits on U.S. 20, which runs through the Wind River Canyon to the south.

Many travelers pass through Thermopolis on road trips between Yellowstone and other parts of Wyoming or Colorado. It makes a good overnight stop with a soak to break up long drives.

Where to stay

Thermopolis has a few hotels and motels, some near the state park, as well as RV parks and campgrounds. Some lodging properties have their own hot springs pools. Book ahead during summer and holiday weekends.

What to bring

Pack the basics for a hot springs visit:

• Swimsuit and towel.
• Sandals or water shoes with good grip.
• A water bottle.
• A bag for wet clothing.
• Warm clothes for after your soak in winter.
• Cash or a card for optional donations or private pools.

Is the water safe?

The state bath house water comes from the park’s mineral springs and is managed by the state for public soaking. As with any hot springs, people with heart conditions, high blood pressure, or pregnancy should talk to a doctor before soaking. Avoid alcohol before and during soaking, and do not put your head underwater.

Follow posted rules and staff instructions. The time limit and other policies are there for safety.

A sample visit

Arrive in Thermopolis in the morning and go straight to the State Bath House for an early soak. Afterward, walk the boardwalks around the terraces and cross the swinging bridge. Drive the bison loop, then have lunch downtown. In the afternoon, visit the Wyoming Dinosaur Center. If you are heading south, drive through Wind River Canyon in late-day light.

How the bath house compares with private pools

Thermopolis has both the free state bath house and commercial pools inside the same park. The difference is mostly in style and price. The bath house is simple and quiet, focused on soaking, with timed sessions and no admission charge. The commercial facilities charge admission and usually offer larger pools, water slides, hot tubs, steam rooms, and longer stays, which can appeal to families with kids.

Many visitors do both: a free soak at the bath house in the morning, then a few hours at a commercial pool later in the day. If you only have time for one, the bath house gives you the most direct connection to the treaty and the tradition of free access. Check each facility’s hours, since they can differ by season and day of the week.

A quick checklist

Before you go, confirm the bath house hours for your day, pack a suit, towel, and sandals, remove silver jewelry, and plan for about 20 minutes in the water. Bring water to drink, and leave time to walk the terraces afterward.

The bottom line

The Thermopolis State Bath House lets you soak in mineral hot springs water for free, usually for about 20 minutes at a time, in indoor and outdoor pools. You walk in, sign in, change, and soak, honoring a public-access provision in the 1896 treaty with the Shoshone and Arapaho. Bring your own suit and towel, plan around the time limit, and pair your soak with the terraces, the bison, and the dinosaurs that make Thermopolis worth a stop.