Casa Diablo Hot Pool
Casa Diablo Hot Pool reaches an intense 165 degrees Fahrenheit at 7,070 feet elevation in the Long Valley Caldera near Mammoth Lakes. This geothermal feature flows approximately 119 degrees above ambient temperature on land owned by the Los Angeles Department of Water and Power.
The pool sits just 155 feet from road access in the eastern Sierra Nevada, accessible by a brief walk through alpine terrain. The immediate landscape shows evidence of active geothermal features, with mineral-stained rocks and steam vents, all set against the backdrop of high-elevation mixed conifer forests with significant winter snowpack exceeding 83 inches annually.
Casa Diablo occupies the Long Valley Caldera, one of California's most significant geothermal systems. The spring's chemistry—with 1,230 mg/L total dissolved solids, high sodium (350 mg/L), and elevated sulfate and chloride—reflects the intense water-rock interaction in this active volcanic environment.
Park at the roadside pullout and enjoy a brief walk to viewing areas. The spring is extremely hot; observe from safe distances and never attempt immersion. Best visited July through September when high-altitude snow clears; winter access may be limited. Sherwin Creek Campground provides nearby overnight options.|
Is Casa Diablo Hot Pool worth visiting?
Best for
- Observing powerful hot springs
- Overnight camping trips
- Mineral-rich therapeutic bathing
Not ideal for
- Casual soaking
The water at Casa Diablo Hot Pool is slightly alkaline (pH 7.7) with 1230 mg/L total dissolved solids. It is notably rich in sodium (supports circulation and skin hydration), chloride (natural antiseptic with skin health benefits), and total dissolved solids (higher mineral concentration for therapeutic soaking).
Some links are affiliate links. We may earn a commission at no extra cost to you.
Overview Sherwin Creek Campground is located in the eastern Sierra Nevada Mountains within 2 miles of the full-service community of Mammoth Lakes, California. Popular among anglers, hikers, off-road vehicle enthusiasts and photographers, the campground is near some of the most spectacular wilderness and outdoor recreation areas in the Sierras.Recreation With a motocross track and trails, Sherwin Creek is a hot spot for off-road vehicle enthusiasts. The area's majestic scenery and challenging...