# Upper Loon Creek Hot Springs, Idaho

Upper Loon Creek Hot Springs in Idaho. 145°F (63°C). Hike · Public Land. Custer County.

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

## Can you soak at Upper Loon Creek Hot Springs?

Yes. Upper Loon Creek Hot Springs has natural, undeveloped pools that run from 90 to 120°F. It's open Jul–Oct. Reaching it takes a hike.

## Key facts

| Fact | Value |
|---|---|
| Source water temperature | 145°F (63°C) (USGS record; developed pools are often cooled) |
| pH | 9.3 (Alkaline) |
| Elevation | 5,080 ft |
| Access | Hike · Public Land, 4.5 mi from the nearest road (Loon Creek Road) |
| Land | Challis National Forest, US Forest Service |
| County | Custer County |
| Nearest town | Challis |
| Coordinates | 44.64500, -114.73900 |
| Best months to soak | December, January, February (largest gap between water and average air temperature) |
| Nearest campground | Custer #1 Campground, 17.4 mi |

## Plan your visit

| | |
|---|---|
| Type | Primitive pools |
| Cost | No fee mentioned in source |
| Season | Jul–Oct |
| Reservations | Not needed |
| Pool temperature | 90–120°F |
| Getting there | 7-8 mi hike north of Loon Creek airstrip on Loon Creek Trail in Frank Church Wilderness; trailhead road open Jul-Oct |
| In winter | Access road closed except Jul-Oct |
| Operator | US Forest Service, Salmon-Challis National Forest |

Checked October 2026. Sources: https://idahohotsprings.com/destinations/upper_loon/index.htm

## Soaking safety

**Very Hot Source, Use Extreme Caution.** At 145°F, the source water at Upper Loon Creek Hot Springs is hot enough to cause burns. Some hot springs this hot have cooler side pools or downstream areas suitable for soaking. Always test the water temperature before entering.

## About Upper Loon Creek Hot Springs

Upper Loon Creek Hot Springs is a hike-in hot spring in Challis National Forest, reached on foot, with source water too hot to touch. Challis is the nearest town at about twenty-seven miles. Access is on record as open. Water chemistry on file shows a strongly alkaline spring with sodium and chloride among the minerals detected. Soaking would mean finding cooled water somewhere, and no pool is described in the record.

Loon Creek Road is the closest road, and from there the springs are four and a half miles farther, on foot. The ground is Forest Service, a little above five thousand feet. Snow in a normal winter runs close to a hundred inches. Otherwise dry.

December through February come out on top on paper, which is a strange recommendation for a four-and-a-half-mile hike through central Idaho snow. Make your own call there. Custer #1 Campground is the nearest camping listed at about seventeen miles, so plan on carrying what you need. The source is scalding. Test the water before you get in and never park yourself where the hot flow arrives. That survey goes back to July 1979.

## Water chemistry

Lab sample from 1979-07-30 (Water Quality Portal).

| Measure | Value |
|---|---|
| pH | 9.3 |
| Calcium | 2 mg/L |
| Magnesium | 0.1 mg/L |
| Sodium | 70 mg/L |
| Sulfate | 43 mg/L |
| Chloride | 8.7 mg/L |

## Nearby

- Nearest city page: [Hot springs near Challis](https://www.soakingsprings.com/hot-springs/near/idaho/challis), 27 mi away
- State page: [Hot springs in Idaho](https://www.soakingsprings.com/hot-springs/idaho)
- [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
- [Foster Ranch Hot Springs, ID](https://www.soakingsprings.com/hot-springs/idaho/foster-ranch-hot-springs): 135°F source, pH 9.1, Hike, near Challis, Custer County
- [Shower Bath Springs, ID](https://www.soakingsprings.com/hot-springs/idaho/shower-bath-springs): 122°F source, pH 9.3, Hike, near Challis, Custer County, primitive pools, free, jul-oct
- [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)
- [Cox Hot Springs, ID](https://www.soakingsprings.com/hot-springs/idaho/cox-hot-springs): 131°F source, pH 8.9, Hike, near Challis, Custer County
- [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)

## Questions

**What is the water temperature at Upper Loon Creek Hot Springs?**
Upper Loon Creek Hot Springs has a water temperature of 145°F (63°C). This is considered a hot spring, well above body temperature.

**Where is Upper Loon Creek Hot Springs located?**
Upper Loon Creek Hot Springs is located in Custer County, Idaho at 5,080 feet elevation, near Challis. Coordinates: 44.6450°N, 114.7390°W.

**How do I get to Upper Loon Creek Hot Springs?**
Upper Loon Creek Hot Springs has Hike road access, with the nearest road being Loon Creek Road (4.5 mi from the road).

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

**Can I camp near Upper Loon Creek Hot Springs?**
Yes, Custer #1 Campground is located nearby (17.4 miles away).

**What minerals are in the water at Upper Loon Creek Hot Springs?**
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 Upper Loon Creek Hot Springs?**
No, not at the source. The water at Upper Loon Creek Hot Springs reaches 145°F, which can cause severe burns within seconds. Look for cooled side pools or downstream stretches, and test with a hand before anything else.

## Sources

- USGS thermal springs records, Water Quality Portal lab analyses, OpenStreetMap, Wikipedia/Wikidata, NOAA climate normals