Thomas Creek Ranch Hot Spring

Custer County, Idaho · Near Challis
44.7210°N, 115.0100°W · 4,400 ft
138°F 32°F air · Good soaking weather 4,400 ft Open Short Walk SDOL Camping nearby (19.1 mi)
Aerial view of the ground around Thomas Creek Ranch Hot Spring LiDAR bare-earth view of the same ground around Thomas Creek Ranch Hot Spring
Aerial LiDAR bare earth

Drag the handle to compare the two views. The orange dot marks the spring, in a frame about three quarters of a mile wide.

Thomas Creek Ranch Hot Spring is hot, near 140 degrees, on state land run by the Idaho Department of Lands in Custer County, about 41 miles from Challis. Access on record is open, and the walk is short, a couple hundred yards. Nothing in the row mentions a ranch, only the state ownership and an SRMA designation.

Location

Around 4,400 feet on Idaho Department of Lands ground, about 350 yards from the closest road. Snow is a bit under a hundred inches a year and precipitation sits in the low twenties. The annual mean lands mid forties. The land carries an SRMA designation, which the record does not expand on. No road name is given, and no fee.

December through February are best, per the record. Boundary Creek Campground is nineteen miles away. The USGS sample is from June 1980 and showed alkaline water. At close to 140 degrees the source will burn; if you soak, it has to be somewhere the water has cooled a lot. Fee is not recorded.

History of Thomas Creek Ranch Hot Spring

The land is held by the Idaho Department of Lands and designated SRMA in the record. The USGS has a site number for the spring with one 1980 sample.

Terrain

Aircraft with laser scanners measured this ground to within inches. The scan strips out trees and buildings, leaving the bare shape of the land around Thomas Creek Ranch Hot Spring.

Setting
Gentle slope
The ground tilts gently up to the north.
Highest ground nearby
136 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
124 milliwatts per square meter of heat flow

That's about twice the US average of 65. It's higher than at 74% 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
26°
Jan
28°
Feb
35°
Mar
40°
Apr
49°
May
60°
Jun
71°
Jul
70°
Aug
60°
Sep
45°
Oct
32°
Nov
23°
Dec
Annual Precip: 22.0 in Annual Snow: 98.3 in
Best Time to Visit
December Air 23°F · Water 138°F · +115° contrast
January Air 26°F · Water 138°F · +112° contrast
February Air 28°F · Water 138°F · +110° contrast
December offers 48°F more contrast than July
Current Conditions
32°F
Clear N 0.0 mph 93% Good soaking weather
Today 78° Low 44° Sunny
Spring is +60° warmer
Wednesday 84° Low 48° Sunny 7% precip
Spring is +54° warmer
Thursday 76° Low 46° Showers And Thunderstorms 81% precip
Spring is +62° warmer
Friday 75° Low 44° Chance Rain Showers 47% precip
Spring is +63° warmer
Saturday 80° Low 46° Sunny 9% precip
Spring is +58° warmer
Water Chemistry Sampled 1980-06-27

The water at Thomas Creek Ranch Hot Spring is alkaline (pH 9.3).

pH 9.3 Alkaline
pH influences mineral absorption through skin
Calcium 2 mg/L
May support bone density and joint health
Magnesium 0 mg/L
Known for muscle relaxation and stress relief
Sodium 86 mg/L
Supports circulation and skin hydration
Sulfate 63 mg/L
Traditionally used for skin conditions and inflammation
Chloride 9 mg/L
Natural antiseptic with skin health benefits
Where to Stay

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Nearby Camping
Boundary Creek Campground 19.1 mi away

Overview Boundary Creek Campground is located at the edge of the Frank Church River of No Return Wilderness, adjacent to the boat launch for the Middle Fork of the Salmon River in Idaho. The site generally provides overnight camping for boaters waiting to launch the next day on their permit to float the Middle Fork. Of the 15 campsites, 5 can be reserved during the high-use season (June 15-Aug. 15); the remaining 10 are first-come, first-served. Outside of those dates, all 15 sites are first-...

Reservable Yes
Reserve on Recreation.gov →
Temperature
138°F
Warm Hot Boiling
Water Temp 138°F (59°C)
Avg Air Temp 45°F
Above Ambient +93°F
Great soaking conditions September
Access
Open
Road Access Short Walk
Distance to Road 0.2 mi
Land
Ownership State
Agency SDOL
Designation SRMA
Unit Idaho Department of Lands
Manager SDOL
Protection 3 - Protected, subject to extractive use
Frequently Asked Questions
What is the water temperature at Thomas Creek Ranch Hot Spring?
Thomas Creek Ranch Hot Spring has a water temperature of 138°F (59°C). This is considered a hot spring, well above body temperature.
Where is Thomas Creek Ranch Hot Spring located?
Thomas Creek Ranch Hot Spring is located in Custer County, Idaho at 4,400 feet elevation, near Challis. Coordinates: 44.7210°N, 115.0100°W.
How do I get to Thomas Creek Ranch Hot Spring?
Thomas Creek Ranch Hot Spring has Short Walk road access (0.2 mi from the road).
Is Thomas Creek Ranch Hot Spring free to visit?
Thomas Creek Ranch Hot Spring has Open access. It is managed by SDOL.
Can I camp near Thomas Creek Ranch Hot Spring?
Yes, Boundary Creek Campground is located nearby (19.1 miles away).
What minerals are in the water at Thomas Creek Ranch Hot Spring?
Water chemistry analysis shows the presence of pH, Calcium, Magnesium, Sodium, Sulfate, Chloride. The pH is 9.3 (alkaline).
Is it safe to soak at Thomas Creek Ranch Hot Spring?
With care. At 138°F Thomas Creek Ranch Hot Spring 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