Warm Spring
An 81-degree spring at 5,720 feet elevation in Cassia County, Idaho, emerging 33.5 degrees above ambient temperature with notably alkaline water at pH 8.5 and low mineralization at 223 mg/L total dissolved solids. Chemistry shows calcium at 36 mg/L, chloride at 57 mg/L, and remarkably low sulfate at 15 mg/L. The spring requires a 212-meter walk from the road near Burley.
Positioned in the mountainous terrain of south-central Idaho, the spring flows in an environment receiving 12 inches annual precipitation and substantial snowfall of 28.9 inches where average temperatures reach 47.5 degrees. The higher elevation compared to nearby valley springs places this feature in foothill country with mixed sagebrush and juniper vegetation. The setting combines open rangeland with forest transitions at higher elevations, reflecting the spring's position between the Snake River Plain and the mountain ranges to the south.
Historical documentation for this spring is not preserved in available sources beyond the generic "Warm Spring" designation common to numerous Idaho thermal features. The spring's chemistry and location suggest it may have served ranching operations during Cassia County's settlement period from the 1870s onward. The strongly alkaline pH and low mineral content distinguish this spring chemically from nearby thermal features, suggesting a distinct flow path through volcanic or metamorphic rocks rather than sedimentary formations.
Visit May through September when mountain access is most reliable; winter snowfall of nearly 29 inches can complicate approach even to roadside locations. The quarter-kilometer walk crosses terrain that likely includes private rangeland; verify access permission before visiting. Water temperature makes this genuinely warm but not hot. Clear Creek Campground, 32.1 kilometers away, offers non-fee primitive camping from June through October with trail access for hiking and horseback riding in the nearby mountains.
Is Warm Spring worth visiting?
Best for
- Warm-water soaking
- Overnight camping trips
The water at Warm Spring is slightly alkaline (pH 8.5) with 223 mg/L total dissolved solids.
Clear Creek Campground is a non-fee campground and picnic area composed of 12 individual units and reservations are not required. This area is accessible for a season that varies usually between June through October. Campground amenities include toilets and the campground is well suited for tent and RV camping. Sites are handicapped accessible. Bull Flat (#001) and Lake Fork (#004) trails are popular with horseback riders, and hikers.