Potosi Warm Springs

Madison County, Montana · Near Virginia City
45.6020°N, 111.9000°W · 6,043 ft
124°F 33°F air · Good soaking weather 6,043 ft Short Walk Camping nearby (16.0 mi)

Despite the name, Potosi Warm Springs reads hot on the record, hotter than most people want to sit in. It is in Madison County, Montana, twenty-one miles from Virginia City and a short way off Willow Meadow Road. A 1977 USGS sample found alkaline water with iron. No owner is listed, and access is not on file.

Location
62 miles from Virginia City, MT

High country by road standards, with a wet climate and heavy snow. Getting to the spring means a short walk from Willow Meadow Road, a bit over a hundred yards. Nothing on record says who holds the land, and no land unit or designation appears.

The temperature on file is hot enough to burn with prolonged contact, so ease in. Red Mountain campground is around sixteen miles away. The listed months are December through February. The snowfall is substantial. Access is not confirmed, and the reading is nearly fifty years old. Nobody has recorded a fee or a bathhouse.

Terrain

USGS hasn't flown a detailed laser scan here yet, so this view comes from aerial photos and older elevation data.

Aerial view of the ground around Potosi Warm Springs

The orange dot marks the spring, in a frame about three quarters of a mile wide.

Setting
Canyon floor
Steep ground climbs away on both sides of the spring.
Highest ground nearby
646 ft above the spring
Within a quarter mile, to the north
Cross-section through the spring

A slice through the ground from southwest to northeast, about 0.6 miles end to end.

Elevation data: USGS 3D Elevation Program. Aerial imagery: USGS The National Map. Public domain.

Heat Below
79 milliwatts per square meter of heat flow

That's close to the US average of 65. It's higher than at 15% of the springs on this site.

Heat flow measures the warmth working its way up through the ground from deep inside the earth. Where it runs high, rain and snowmelt that seep down through cracks in the rock come back up hot.

Heat flow estimate: Stanford Thermal Earth Model (Aljubran & Horne, 2024), CC BY 4.0.

Monthly Climate
18°
Jan
18°
Feb
27°
Mar
35°
Apr
45°
May
55°
Jun
65°
Jul
64°
Aug
54°
Sep
39°
Oct
26°
Nov
17°
Dec
Annual Precip: 25.8 in Annual Snow: 64.5 in
Best Time to Visit
December Air 17°F · Water 124°F · +108° contrast
January Air 18°F · Water 124°F · +106° contrast
February Air 18°F · Water 124°F · +106° contrast
December offers 49°F more contrast than July
Current Conditions
33°F
Good soaking weather
Today 62° Low 39° Sunny 1% precip
Spring is +62° warmer
Wednesday 60° Low 43° Sunny 5% precip
Spring is +64° warmer
Thursday 66° Low 47° Partly Sunny then Showers And Thunderstorms Likely 61% precip
Spring is +58° warmer
Friday 60° Low 44° Rain Showers 76% precip
Spring is +64° warmer
Saturday 63° Low 45° Slight Chance Light Rain 20% precip
Spring is +61° warmer
Water Chemistry Sampled 1977-01-15

The water at Potosi Warm Springs is slightly alkaline (pH 8.3).

pH 8.3 Slightly Alkaline
pH influences mineral absorption through skin
Calcium 10 mg/L
May support bone density and joint health
Magnesium 0 mg/L
Known for muscle relaxation and stress relief
Sodium 88 mg/L
Supports circulation and skin hydration
Sulfate 98 mg/L
Traditionally used for skin conditions and inflammation
Chloride 5 mg/L
Natural antiseptic with skin health benefits
Iron 60 µg/L
Iron-rich springs may support circulation
Where to Stay

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Nearby Camping
Red Mountain (Mt) 16.0 mi away

Overview The Dillon Field Office is unable to make reservations for you. Please call Recreation.gov (877-444-6777) to book a reservation or book online. Campsites are available for reservation for the Peak-Season times of May 1st through September 15th. From September 16th through April 30th, all sites are first-come-first-serve. Red Mountain Campground is adjacent to the lower Madison River and provides good access for camping, fishing and floating. The campground has 19 camp sites, 11 ava...

Reservable Yes
Reserve on Recreation.gov →
Mile-High Advisory 6,043 ft

Potosi Warm Springs sits at 6,043 feet above sea level, way above the mile-high mark. You may not feel the altitude strongly, but hot water still dehydrates you faster at elevation. UV is about 24% stronger than at sea level, so bring sunscreen and drink more water than you normally would.

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Temperature
124°F
Warm Hot Boiling
Water Temp 124°F (51°C)
Avg Air Temp 39°F
Above Ambient +85°F
Great soaking conditions September
Access
Road Access Short Walk
Nearest Road Willow Meadow Road
Distance to Road 363 ft
Frequently Asked Questions
What is the water temperature at Potosi Warm Springs?
Potosi Warm Springs has a water temperature of 124°F (51°C). This is considered a hot spring, well above body temperature.
Where is Potosi Warm Springs located?
Potosi Warm Springs is located in Madison County, Montana at 6,043 feet elevation, near Virginia City. Coordinates: 45.6020°N, 111.9000°W.
How do I get to Potosi Warm Springs?
Potosi Warm Springs has Short Walk road access, with the nearest road being Willow Meadow Road (363 ft from the road).
Can I camp near Potosi Warm Springs?
Yes, Red Mountain (Mt) is located nearby (16.0 miles away).
What minerals are in the water at Potosi Warm Springs?
Water chemistry analysis shows the presence of pH, Calcium, Magnesium, Sodium, Sulfate, Chloride, Iron. The pH is 8.3 (slightly alkaline).
Is it safe to soak at Potosi Warm Springs?
With care. At 124°F Potosi Warm Springs is hot enough to need short sessions, fifteen to twenty minutes, and plenty of water. Enter slowly and get out if you feel light-headed.
Sources: USGS NWIS