Granite Creek Hot Spring
Granite Creek Hot Spring delivers 131°F water along Middle Fork Road in the Boise National Forest at 4,205 feet, with a pH of 9.4 that makes the water feel almost oily against the skin. The source sits just 240 feet from the road, offering genuine hot spring water without the hike.
The spring emerges near the roadside where Middle Fork Road traces a narrow valley through ponderosa pine and Douglas fir. The water carries virtually no calcium or magnesium, giving it an unusually soft, slippery texture. Steam rises from the source year-round, thickening in winter when temperatures drop well below freezing and snow accumulates past 10 feet. The forest floor around the spring stays green and mossy from constant thermal moisture.
The water chemistry tells the geological story: sodium-dominant at 52 mg/L with zero detectable magnesium, this water has spent significant time circulating through deep granitic rock of the Idaho Batholith. The high pH of 9.4 and near-absence of calcium at 1.9 mg/L indicate the water rose quickly through relatively unfractured rock, picking up little dissolved mineral along the way.
Access from Middle Fork Road is a short walk of about 240 feet. The source temperature of 131°F is dangerously hot at the point of emergence, so test carefully before entering any pooled area. The historic Barber Flat Cabin, a CCC-built structure from 1935, is reservable about 11 miles away. Bring drinking water and pack out all trash.
Is Granite Creek Hot Spring worth visiting?
Best for
- Hot spring soaking
- Easy day trips
- Overnight camping trips
The water at Granite Creek Hot Spring is alkaline (pH 9.4).
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Overview The Barber Flat Cabin site was established for administrative use by the Forest Service in 1923, and was used prior to that by the Barber Lumber Company. At the time, the Forest Service used a cabin already on-site as a guard station and then built a new one in 1927. The current cabin and outbuildings were built by the Civilian Conservation Corps in 1935, and the cabin today looks much as it did back then. Guests can drive to Barber Flat Cabin in two-wheel drive passenger cars or tr...