Upper Loon Creek Hot Springs
Drag the handle to compare the two views. The orange dot marks the spring, in a frame about three quarters of a mile wide.
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.
Aircraft with laser scanners measured this ground to within inches. The scan strips out trees and buildings, leaving the bare shape of the land around Upper Loon Creek Hot Springs.
- Setting
- Canyon floor
- Steep ground climbs away on both sides of the spring.
- Highest ground nearby
- 772 ft above the spring
- Within a quarter mile, to the southeast
A slice through the ground from northwest to southeast, about 0.6 miles end to end.
Elevation data: USGS 3D Elevation Program. Aerial imagery: USGS The National Map. Public domain.
That's about twice the US average of 65. It's higher than at 67% of the springs on this site.
Heat flow measures the warmth working its way up through the ground from deep inside the earth. Where it runs high, rain and snowmelt that seep down through cracks in the rock come back up hot.
See every spring on the geothermal heat map →
Heat flow estimate: Stanford Thermal Earth Model (Aljubran & Horne, 2024), CC BY 4.0.
The water at Upper Loon Creek Hot Springs is alkaline (pH 9.3).
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This campground is along the Custer Motorway just above the townsite of Custer, a boom town during the late 1800's. Visit the museum, open 9 - 5 Memorial Day through Labor Day. Facilities include 6 sites with picnic tables and fire rings with cooking grills. Campground has a vault toilet and can accommodate trailers and motorhomes up to 32 feet long.
Upper Loon Creek Hot Springs is road-accessible, so you can bring more gear. The water is dangerously hot, so bring water shoes and test pools carefully. Cold air temperatures make a changing robe or warm layers essential.
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