Potosi Hot Springs

Two places, one name

“Potosi Hot Springs” means two different things in the Tobacco Root Mountains, and it matters which one you are planning for.

The first is a small, undeveloped pool a short walk from Potosi Campground, a rustic Forest Service campground at the top of South Willow Creek southwest of Pony. That is the place this page is about. It is free, it is on a public trail, and as far as any recent source shows, it is still there to use.

The second is the Potosi Hot Springs resort, a private property farther down the creek with a large pool, an indoor tub, a sauna and cabins. Its status is unclear. It closed to the public in 2007, reopened in a limited form in 2018 with cabin rentals and private pool bookings, and was described in 2024 as closed to public access until 2025. In October 2026 the resort’s former website address shows unrelated gambling content. Do not drive up expecting to buy a day pass.

What to expect at the wild pool

The pool is small and simple. A 2017 Bozeman Daily Chronicle feature described it as fenced, roomy enough for about 10 people, with one small stream feeding it and another carrying the overflow away. Outside Bozeman sized it for four to six. Either way, it is a backcountry soak, not a swimming pool.

The water is warm rather than hot. The Chronicle writer called it refreshingly warm on a fall day when the air barely reached 50°F10°C, and Outside Bozeman notes it is not the warmest pool around. No agency publishes a temperature. Spring water at the resort downstream has been listed at about 93°F34°C, which gives a rough idea. This is a pool for long, mild soaks in summer and early fall, not a place to thaw out in January.

The setting is high forest on the east side of the Tobacco Roots, with Willow Creek running nearby. There are no facilities at the pool itself.

Getting there

Pony is a small former mining town at the foot of the Tobacco Roots, about an hour from Bozeman. From US-287 at Harrison, take the paved road west to Pony.

At the edge of Pony, turn south onto the dirt road (Potosi Road and then South Willow Creek Road) and follow the signs to Potosi Campground. It is about 8 miles, past ranches, old rock walls and the creek. The road is rough, with deep bumps and potholes, so drive slowly. A normal car usually manages it in dry weather; higher clearance helps. In winter and spring the upper road can hold snow and mud.

The trail starts at the campground. It is under a mile, climbs a short hill, then turns left and drops to the springs. Bring a headlamp if you might walk back after dark.

When to go

Late summer to October is the sweet spot. The road is dry, the creek is down and the pool’s mild temperature feels right on a cool evening. Summer weekends are the busy time, because campers at Potosi Campground walk over in the evenings. A weekday visit, or a soak in the early morning, gives you the best chance of having it to yourself.

Winter visits are possible if the road is passable, but the pool is not hot enough to make that worthwhile for most people, and snow on the Pony road can stop you well short of the campground.

Rules and etiquette

• Free, but fragile. There is no fee for the pool. Do not dig, dam or move rocks.
• Pack it out. No trash cans at the springs. Carry out everything, including food scraps and toilet paper.
• Food storage order. The Beaverhead-Deerlodge National Forest food storage order (02-00-22-02) runs from March 1 to December 1 each year. Food, trash and scented items must be in a bear-resistant container, a hard-sided vehicle, or hung, unless you are awake and within 100 feet of them.
• Camping limits. The Northern Region order R1-2025-01 (Aug 1, 2025 to July 31, 2030) limits camping on Montana national forests to 16 days at one site and 32 days a year. It also bans burning pallets or wood with nails.
• Stay on public ground. The resort’s private land begins farther down the creek. Do not follow the creek onto it or try to use the resort’s pool without the owners’ permission.
• Clothing. No posted rule turned up in our research. This is a small pool next to a family campground, so bring a swimsuit and read the room.

The resort’s history

The resort side has a long and bumpy story. In 1892 Horace Walter, an Indiana carpenter, built a pool, bathhouse and hotel at the springs. The property changed hands several times and was abandoned for a while. In the 1960s it drew a counterculture crowd, and by 1971 local ranchers and the sheriff had cleared out the squatters, burned their shacks and blasted a pool wall. A Texas family bought the resort in 2007 and closed it to the public. New owners took over in 2018 and opened four cabins and private pool bookings. Recent listings describe a 25 by 50 foot pool fed by water of about 93°F34°C, an indoor tub and a wood-fired sauna.

Where to stay nearby

• Potosi Campground, the Forest Service site at the trailhead, is small and rustic. Arrive early on summer weekends.
• Pony has the Pony Bar, which has served dinner on weekends, and little else. Harrison, on US-287, has the nearest store.
• Norris Hot Springs, on the other side of the Tobacco Roots near the Madison River, is a developed public pool and the easy hot soak to pair with this one.
• Pipestone Village and Hot Springs, west of Whitehall, rents cabins with private hot-spring tubs.

Safety notes

• Wildlife: Bears and moose use this drainage. A 2017 visitor found a carcass notice posted near the pool and bear warnings along the trail. Carry bear spray, make noise on the trail and keep food in your vehicle.
• Water quality: The pool is small and untreated. Keep your head above water.
• Remote road: Help is far away and cell service is unreliable past Pony. Carry a spare tire and tell someone where you are going.
• Cold nights: Even in summer, nights at the campground can be cold. Have warm clothes for the walk back after a soak.