Unnamed Thermal Spring
High in the Sierra National Forest near Mammoth Lakes, this 95-degree thermal spring flows at 5,585 feet elevation, creating 46 degrees of warmth in spectacular mountain backcountry.
The spring emerges in the high Sierra landscape, requiring a substantial 2,400-meter hike from Edison Lake access. Mixed conifer forest dominates the terrain, with exposed granite peaks visible from higher elevations. Average annual precipitation reaches 36.3 inches, with over 175 inches of snowfall creating deep pack conditions for much of the year.
Geologically, this spring indicates strong geothermal circulation in the Sierra Nevada's complex fault systems. The site sits within the John Muir and Ansel Adams Wilderness areas, among the most protected and pristine landscapes in California, managed by the U.S. Forest Service for wilderness preservation.
Access requires a 2,400-meter hike from the nearest road, positioning this spring firmly in the backcountry. Plan for a full day or overnight trip with proper wilderness gear. Summer and early fall offer the best access window, with snow typically clearing by late June. Vermillion Campground on Edison Lake lies 11.7 kilometers away.
Is this spring worth visiting?
Best for
- Warm-water soaking
- Overnight camping trips
Overview Vermillion Campground is located on the northwest shore of Edison Lake, in a shady stand of Ponderosa pine. Most sites provide lake views. The campground is ideal for tents, as well as small RVs. Visitors can enjoy mountain views of the surrounding John Muir and Ansel Adams Wilderness areas.Recreation Edison Lake has a free public boat launch. Canoeing and kayaking near the shoreline are popular activities. Anglers can fish for rainbow, brown or brook trout. Sandy beaches within the...