Cronks Canyon Hot Spring
Cronks Canyon Hot Spring sits at a comfortable 115 degrees Fahrenheit along the Salmon River Scenic Byway in Custer County, one of central Idaho's more accessible backcountry soaks. On BLM land with open public access, the spring requires only a short walk of about 345 feet from the byway to reach the thermal outflow.
The canyon walls along the Salmon River corridor frame the spring in exposed rock and sparse vegetation at 4,740 feet elevation. Winters here are cold, with nearly five feet of annual snowfall, and the contrast between hot mineral water and frigid air creates visible steam from fall through spring. The Salmon River Scenic Byway winds nearby, its two-lane road following the river through narrow canyons. The air is dry and clean, carrying the scent of sage and warm mineral water.
Cronks Canyon sits within the broader geothermal province of central Idaho, where deep faults channel heated water to the surface along the Salmon River corridor. The water carries 160 mg/L sodium with moderate sulfate and chloride levels, suggesting a moderate-depth circulation system. The mildly alkaline pH of 7.9 and USGS-confirmed temperature of 45.5 degrees Celsius reflect stable geothermal conditions that have persisted for thousands of years along these ancient fault lines.
The 115-degree temperature is hot but approachable for soaking where the water has cooled slightly downstream. The spring is on BLM land managed by the Challis Field Office, and access is open to the public. Iron Lake Campground lies about 15 miles away but is first-come, first-served with no reservations. The Salmon River Scenic Byway provides year-round road access, though winter driving requires caution.
Is Cronks Canyon Hot Spring worth visiting?
Best for
- Hot spring soaking
- Overnight camping trips
The water at Cronks Canyon Hot Spring is slightly alkaline (pH 7.9).
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Eight campsites with picnic tables and fire rings are along the shores of this high alpine lake. the campground has piped drinking water and vault toilets but no garbage services are available. The trail from campground leads to more lake fishing, at the Hat Lakes to the south. Carry-down access for non motorized boats to the lakes. The drive in along Salmon River Mountain Road, offers spectacular views of craggy peaks and deep pine forests.