# Cox Hot Springs, Idaho

Cox Hot Springs in Idaho. 131°F (55°C). Hike · Public Land. Custer County.

- Page: https://www.soakingsprings.com/hot-springs/idaho/cox-hot-springs
- Source: Soaking Springs, researched and maintained by Armen Suny
- Updated: 2026-09-14

## Can you soak at Cox Hot Springs?

Only once it cools. The water leaves the ground at 131°F, hotter than any hot tub. Reaching it takes a hike. It's on US Forest Service land. We haven't confirmed whether it has a pool or charges a fee.

## Key facts

| Fact | Value |
|---|---|
| Source water temperature | 131°F (55°C) (USGS record; developed pools are often cooled) |
| pH | 8.9 (Alkaline) |
| Elevation | 4,160 ft |
| Access | Hike · Public Land, 2.7 mi from the nearest road |
| Land | Boise National Forest, US Forest Service |
| County | Custer County |
| Nearest town | Challis |
| Coordinates | 44.78500, -114.85500 |
| Best months to soak | December, January, February (largest gap between water and average air temperature) |
| Nearest campground | YELLOWJACKET GUARD STATION, 23.3 mi |

## About Cox Hot Springs

Backcountry, and a long way from anything: Cox Hot Springs sits in Custer County within the Boise National Forest per the record, 36 miles from Challis, and nothing closer counts as a town. Hot water, low 130s. The record marks access open. OpenStreetMap uses the same name. This is a hike-in spring with a photograph on file and nothing in the way of facilities.

The walk is about two and three quarter miles from the closest road, one with no name on file. Elevation is middling for central Idaho. Snow comes in at close to eight feet a winter and the climate is otherwise moderate. Yellowjacket Guard Station is the closest listed camping, 23 miles away, so this is a long approach in both senses.

Winter gets the best-months tag, which for a near three mile hike through that much snow calls for snowshoes or waiting for the melt. Cooling is required before anyone sits in it. The chemistry was run in 1980 and came back alkaline. There is no developed camping anywhere near the spring; the guard station is the closest thing on file.

## Water chemistry

Lab sample from 1980-06-28 (Water Quality Portal).

| Measure | Value |
|---|---|
| pH | 8.9 |
| Calcium | 1.8 mg/L |
| Sodium | 100 mg/L |
| Sulfate | 47 mg/L |
| Chloride | 12 mg/L |

## Nearby

- Nearest city page: [Hot springs near Challis](https://www.soakingsprings.com/hot-springs/near/idaho/challis), 36 mi away
- State page: [Hot springs in Idaho](https://www.soakingsprings.com/hot-springs/idaho)
- [Lower Loon Creek Hot Spring, ID](https://www.soakingsprings.com/hot-springs/idaho/lower-loon-creek-hot-spring): 120°F source, pH 9.0, Short Walk, near Challis, Custer County, primitive pools, parking or permit fee, late may-sep (river permit season)
- [Hospital Hot Spring, ID](https://www.soakingsprings.com/hot-springs/idaho/hospital-hot-spring): 115°F source, pH 8.9, TDS 278 mg/L, Hike, near Challis, Custer County, primitive pools, parking or permit fee, late may-sep (river permit season)
- [Sunflower Hot Springs, ID](https://www.soakingsprings.com/hot-springs/idaho/sunflower-hot-springs): 149°F source, pH 9.3, Short Walk, near Challis, Custer County, primitive pools
- [Sunflower Flat Hot Spring, ID](https://www.soakingsprings.com/hot-springs/idaho/sunflower-flat-hot-spring): 109°F source, pH 9.2, Short Walk, near Challis, Custer County
- [Thomas Creek Ranch Hot Spring, ID](https://www.soakingsprings.com/hot-springs/idaho/thomas-creek-ranch-hot-spring): 138°F source, pH 9.3, Short Walk, near Challis, Custer County
- [Owen Cabin Hot Spring, ID](https://www.soakingsprings.com/hot-springs/idaho/owen-cabin-hot-spring): 133°F source, pH 9.3, Hike, near Challis, Custer County

## Questions

**What is the water temperature at Cox Hot Springs?**
Cox Hot Springs has a water temperature of 131°F (55°C). This is considered a hot spring, well above body temperature.

**Where is Cox Hot Springs located?**
Cox Hot Springs is located in Custer County, Idaho at 4,160 feet elevation, near Challis. Coordinates: 44.7850°N, 114.8550°W.

**How do I get to Cox Hot Springs?**
Cox Hot Springs has Hike road access (2.7 mi from the road).

**Is Cox Hot Springs free to visit?**
Cox Hot Springs has Open access. It is managed by US Forest Service.

**Can I camp near Cox Hot Springs?**
Yes, Yellowjacket Guard Station is located nearby (23.3 miles away).

**What minerals are in the water at Cox Hot Springs?**
Water chemistry analysis shows the presence of pH, Calcium, Sodium, Sulfate, Chloride. The pH is 8.9 (alkaline).

**Is it safe to soak at Cox Hot Springs?**
With care. At 131°F Cox Hot 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 thermal springs records, Water Quality Portal lab analyses, OpenStreetMap, Wikipedia/Wikidata, NOAA climate normals
- https://en.wikipedia.org/wiki/Hot_spring