# South Fork Plunge, Idaho

South Fork Plunge in Idaho. 129°F (54°C). Short Walk · Public Land. Valley County.

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

## Can you soak at South Fork Plunge?

Only once it cools. The water leaves the ground at 129°F, hotter than any hot tub. It's a short walk from the road. 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 | 129°F (54°C) (USGS record; developed pools are often cooled) |
| Elevation | 5,360 ft |
| Access | Short Walk · Public Land, 0.2 mi from the nearest road (South Fork Road) |
| Land | Boise National Forest, US Forest Service |
| County | Valley County |
| Nearest town | Cascade |
| Coordinates | 44.63200, -115.69700 |
| Best months to soak | December, January, February (largest gap between water and average air temperature) |
| Nearest campground | PICNIC POINT (ID), 1.8 mi |

## About South Fork Plunge

South Fork Plunge, mapped on OpenStreetMap as Molly's Tub, is a hot spring in the Boise National Forest near Cascade, in Valley County. Water comes up close to 130 degrees, hot enough that it needs cooling before anyone sits in it. It is a couple hundred yards from South Fork Road. Access is open.

Forest Service land at roughly 5,400 feet, reached by a short walk of a fifth of a mile off South Fork Road. Snow is extreme here, an average near 210 inches, and precipitation overall runs above forty inches. Year-round temperatures average in the low forties. Expect snow on the ground for much of the year.

Two names are in play. The USGS and this listing call it South Fork Plunge. OpenStreetMap calls it Molly's Tub.

The listed best months are December through February, which with this much snow means skis or snowshoes, or a wait until things melt. Picnic Point campground lies less than two miles away. Water near 130 degrees will burn; find where it has cooled before getting in. No fee is noted.

## Nearby

- Nearest city page: [Hot springs near Challis](https://www.soakingsprings.com/hot-springs/near/idaho/challis), 50 mi away
- State page: [Hot springs in Idaho](https://www.soakingsprings.com/hot-springs/idaho)
- [Mollys Hot Spring, ID](https://www.soakingsprings.com/hot-springs/idaho/mollys-hot-spring): 138°F source, pH 9.3, Roadside, near Cascade, Valley County, primitive pools, free, may–oct
- [Warm Lake Springs, ID](https://www.soakingsprings.com/hot-springs/idaho/warm-lake-springs): Warm, TDS 258 mg/L, Short Walk, near Cascade, Valley County
- [Trail Creek Hot Spring, ID](https://www.soakingsprings.com/hot-springs/idaho/trail-creek-hot-spring): 122°F source, pH 9.7, Short Walk, near Cascade, Valley County, primitive pools, pools 100–110°F, free, year-round
- [Vulcan Hot Springs, ID](https://www.soakingsprings.com/hot-springs/idaho/vulcan-hot-springs): 190°F source, pH 9.1, Short Walk, near Cascade, Valley County, primitive pools, free, apr–oct
- [Dollar Creek Warm Spring, ID](https://www.soakingsprings.com/hot-springs/idaho/dollar-creek-warm-spring): 68°F source, pH 7.7, Roadside, near Cascade, Valley County
- [Billy Hot Spring, ID](https://www.soakingsprings.com/hot-springs/idaho/billy-hot-spring): Hot, pH 9.7, Short Walk, near Cascade, Valley County

## Questions

**What is the water temperature at South Fork Plunge?**
South Fork Plunge has a water temperature of 129°F (54°C). This is considered a hot spring, well above body temperature.

**Where is South Fork Plunge located?**
South Fork Plunge is located in Valley County, Idaho at 5,360 feet elevation, near Cascade. Coordinates: 44.6320°N, 115.6970°W.

**How do I get to South Fork Plunge?**
South Fork Plunge has Short Walk road access, with the nearest road being South Fork Road (0.2 mi from the road).

**Is South Fork Plunge free to visit?**
South Fork Plunge has Open access. It is managed by US Forest Service.

**Can I camp near South Fork Plunge?**
Yes, Picnic Point (Id) is located nearby (1.8 miles away).

**Is it safe to soak at South Fork Plunge?**
With care. At 129°F South Fork Plunge 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