Middle Fork Indian Creek Hot Spring
Middle Fork Indian Creek Hot Spring erupts at 162 degrees Fahrenheit deep within the Boise National Forest, with USGS measurements recording 87 degrees Celsius and a strongly alkaline pH of 9.0. Reaching it requires a nearly 5-mile hike into the backcountry east of the Frank Church-River of No Return Wilderness, at 5,438 feet elevation in Custer County.
The trail crosses dense mountain forest where annual snowfall exceeds 108 inches and the average temperature sits at just 42 degrees. At the source, superheated water issues from fractured granite, and steam hangs in the cold mountain air through most of the year. The surrounding landscape is steep, forested, and wild, with few signs of human presence. Sulfate levels of 66 milligrams per liter give the water a faint mineral edge, and the low calcium of just 2 milligrams per liter reflects the granitic bedrock.
This spring taps the deep geothermal system associated with the Idaho Batholith, where fractured granite allows water to descend miles into the earth before returning superheated to the surface. The pH of 9.0 and sodium-dominant chemistry with 110 milligrams per liter sodium are characteristic of hot springs emerging from granitic terrain. The nearby Frank Church-River of No Return Wilderness preserves more than 2.3 million acres of similar geology, making central Idaho one of the most thermally active regions in the lower 48 states.
The roughly 5-mile hike from the nearest road demands proper backcountry preparation including topographic maps, adequate water, and layered clothing for rapid weather changes. The source water at 162 degrees causes immediate burns. Johnson Creek Guard Station, a reservable Forest Service cabin 19 miles away, offers a comfortable base with modern amenities from June through September. Contact the Boise National Forest for current trail conditions and fire restrictions before heading out.
Is Middle Fork Indian Creek Hot Spring worth visiting?
Best for
- Observing powerful hot springs
- Overnight camping trips
Not ideal for
- Casual soaking
The water at Middle Fork Indian Creek Hot Spring is alkaline (pH 9.0).
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Overview Johnson Creek Guard Station was built in 1922 and offers a charming mountain respite with modern conveniences. The cabin offers nearly everything needed for a pleasant and comfortable stay. Peak season for the cabin is typically early June through late September. It can be accessed by most vehicles via dirt and gravel roads, but trailers are not recommended.Recreation The cabin is near several trailheads into the Frank Church - River of No Return Wilderness. These non-motorized tr...