# Sunflower Hot Springs, Idaho

Sunflower Hot Springs in Idaho. 149°F (65°C). Short Walk · Public Land. Custer County.

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

## Can you soak at Sunflower Hot Springs?

Yes. Sunflower Hot Springs has natural, undeveloped pools. It's a short walk from the road.

## Key facts

| Fact | Value |
|---|---|
| Source water temperature | 149°F (65°C) (USGS record; developed pools are often cooled) |
| pH | 9.3 (Alkaline) |
| Elevation | 4,375 ft |
| Access | Short Walk · Public Land, 0.5 mi from the nearest road |
| Land | Boise National Forest, US Forest Service |
| County | Custer County |
| Nearest town | Challis |
| Coordinates | 44.73000, -114.99300 |
| Best months to soak | December, January, February (largest gap between water and average air temperature) |
| Nearest campground | BOUNDARY CREEK CAMPGROUND, 20.1 mi |

## Plan your visit

| | |
|---|---|
| Type | Primitive pools |
| Cost | Reached on Middle Fork Salmon float trips; river permit system applies, no site fee found |
| Getting there | Boat access on Middle Fork Salmon River (Frank Church Wilderness) or long backcountry hike |
| In winter | n/a, river access in float season |
| Operator | US Forest Service, Salmon-Challis National Forest |

Checked October 2026. Sources: https://en.wikipedia.org/wiki/Sunflower_Hot_Springs, https://www.nwrafting.com/middle-fork-of-the-salmon/hot-springs-on-the-middle-fork-of-the-salmon-river, https://www.recreation.gov/permits/234623

## Soaking safety

**Very Hot Source, Use Extreme Caution.** At 149°F, the source water at Sunflower 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 Sunflower Hot Springs

Sunflower Hot Springs comes out scalding, near 150 degrees, on Boise National Forest land in Custer County around 40 miles from Challis. Wikipedia calls it a geothermal mineral spring. The approach is half a mile of walking and access is marked open. The source water is far too hot to enter.

The spring sits at roughly 4,400 feet in country that sees snowfall short of a hundred inches and modest precipitation, averaging mid forties across the year. It is half a mile in from the road, and no one has written down which road. Forest Service land with a plain National Forest designation and no fee mentioned.

Wikipedia's short entry places Sunflower Hot Springs within Boise National Forest and calls the water geothermal and mineral. OpenStreetMap and the USGS both carry the same name.

December to February is the listed window. Boundary Creek Campground is twenty miles away. The 1980 USGS sample found alkaline water. At nearly 150 degrees the water will burn skin on contact; only a pool that has cooled well below that is safe, and the record says nothing about one existing.

## Water chemistry

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

| Measure | Value |
|---|---|
| pH | 9.3 |
| Calcium | 2.4 mg/L |
| Magnesium | 0.2 mg/L |
| Sodium | 75 mg/L |
| Sulfate | 48 mg/L |
| Chloride | 8.1 mg/L |

## Nearby

- Nearest city page: [Hot springs near Challis](https://www.soakingsprings.com/hot-springs/near/idaho/challis), 33 mi away
- State page: [Hot springs in Idaho](https://www.soakingsprings.com/hot-springs/idaho)
- [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
- [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
- [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
- [Indian Creek Hot Spring, ID](https://www.soakingsprings.com/hot-springs/idaho/indian-creek-hot-spring): 190°F source, pH 9.0, Hike, near Challis, Custer County
- [Middle Fork Indian Creek Hot Spring, ID](https://www.soakingsprings.com/hot-springs/idaho/middle-fork-indian-creek-hot-spring): 162°F source, pH 9.0, Hike, near Challis, Custer County
- [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)

## Questions

**What is the water temperature at Sunflower Hot Springs?**
Sunflower Hot Springs has a water temperature of 149°F (65°C). This is considered a hot spring, well above body temperature.

**Where is Sunflower Hot Springs located?**
Sunflower Hot Springs is located in Custer County, Idaho at 4,375 feet elevation, near Challis. Coordinates: 44.7300°N, 114.9930°W.

**How do I get to Sunflower Hot Springs?**
Sunflower Hot Springs has Short Walk road access (0.5 mi from the road).

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

**Can I camp near Sunflower Hot Springs?**
Yes, Boundary Creek Campground is located nearby (20.1 miles away).

**What minerals are in the water at Sunflower 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 Sunflower Hot Springs?**
No, not at the source. The water at Sunflower Hot Springs reaches 149°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
- https://en.wikipedia.org/wiki/Sunflower_Hot_Springs