Natural hot spring · Idaho
Cox Hot Springs
Custer County, Idaho · 36 miles northwest of Challis, ID
Last updated
- Type
- Natural Natural hot spring
- Water temperature
- 131°F (55°C) at the source
- Cost
- Not recorded
- Hours or season
- Not recorded
- Clothing
- Not recorded
- Nearest town
- Challis, ID (36 mi / 58 km)
- Coordinates
- Pools or sources
- 1
- Scalding: recorded at 50°C or above. Water at this temperature causes burns in seconds.
About Cox Hot Springs
Cox Hot Springs is a natural hot spring in Custer County, Idaho, about 36 miles northwest of Challis, ID. The nearest large city is Boise, ID, roughly 105 miles away as the crow flies.
The temperature at the source has been recorded at 131°F (55°C). That puts it in the "too hot to enter at the source" range. Water this hot can burn skin quickly. Soaking pools are usually cooled by mixing with creek or tap water. Never enter the source itself.
It is a natural spring with little or no development. Some natural springs have rock pools you can sit in, while others are too hot, too shallow or on land where soaking is not allowed.
Water temperature
Too hot to enter at the source. Water this hot can burn skin quickly. Soaking pools are usually cooled by mixing with creek or tap water. Never enter the source itself.
Readings come from the NOAA thermal springs list, OpenStreetMap mappers, and other public sources. Temperatures change with season, flow and pool design. See our soak temperature guide for safe soaking times.
Map and directions
Red marks Cox Hot Springs. Other colored dots are nearby springs in this directory. Coordinates: 44.78500, -114.85500.
Getting there
- Nearest town: Challis, ID. The spring is about 36 miles (58 km) northwest of town in a straight line.
- Nearest large city: Boise, ID, about 105 miles (169 km) in a straight line.
- Use the directions buttons above for a driving route. Final roads to many springs are unpaved, seasonal or closed in winter, so check road conditions before you go.
Weather forecast
Live forecast for this exact spot from the US National Weather Service.
Hot springs near Cox Hot Springs
- Loon Creek Hot Spring 120°F
- Hospital Hot Spring 115°F
- Sunflower Hot Springs 149°F
- Sunflower Flat Hot Spring 109°F
- Owen Cabin Hot Spring 133°F
- Upper Loon Creek Hot Springs 145°F
Before you go
- Check the operator, land manager or park website for current hours, fees and closures. Details in any directory can go out of date.
- Pack out everything you bring, including food scraps. Do not use soap in natural pools.
- Keep your head above water. Warm fresh water can carry Naegleria fowleri, a rare but deadly amoeba that enters through the nose.
- Drink water, limit soaks to 10 to 20 minutes at a time in very hot water, and skip alcohol.
- Read our hot spring etiquette guide and safety guide.
Frequently asked questions
How hot is Cox Hot Springs?
The temperature at the source has been recorded at 131°F (55°C), which is too hot to enter at the source. Water this hot can burn skin quickly. Soaking pools are usually cooled by mixing with creek or tap water. Never enter the source itself.
Where is Cox Hot Springs?
Cox Hot Springs is in Custer County, Idaho, about 36 miles northwest of Challis, ID. The GPS coordinates are 44.7850, -114.8550.
Can you soak at Cox Hot Springs?
The source is too hot to enter safely. Natural springs vary. Some have pools built by visitors, others are too hot or shallow, and some are on private land or in areas where bathing is banned. Check local rules and test the water before you get in.
What hot springs are near Cox Hot Springs?
The closest listed spring is Loon Creek Hot Spring, about 2.6 miles east. Hospital Hot Spring is about 4.7 miles away.
What should I bring to a hot spring?
Water to drink, a towel, sandals with grip, a bag to pack out trash, and warm layers for after your soak. At primitive springs bring a headlamp and tell someone where you are going.
Sources and corrections
This listing combines the NOAA NCEI Thermal Springs List, OpenStreetMap. Data last refreshed August 2026. Source 1 Source 2
Visited recently? Send a correction, such as a temperature reading, fee, closure or photo. If you look after this spring and want it removed, see removal requests.