Sierra Nevada Geothermal Hot Springs

Sierra Nevada Geothermal Hot Springs near Mammoth Lakes in Mono County, California, are a collection of natural hot springs associated with the Long Valley Caldera — one of the most volcanically active regions in the western United States, where a supervolcanic eruption 760,000 years ago created a massive caldera and where ongoing geothermal activity continues to heat groundwater in multiple accessible spring systems. The chloride and bicarbonate-rich geothermal waters emerge at various temperatures in the volcanic landscape around Mammoth Mountain — a major ski resort created by eruptions — and along the banks of Hot Creek, where naturally warm and boiling springs mix in a protected geological study area. The Mammoth Lakes region's extraordinary combination of volcanic geology, high-altitude alpine scenery, world-class skiing, rock climbing, and access to Yosemite National Park makes it one of California's most active outdoor adventure destinations, with natural hot spring bathing providing a perfect restorative counterpoint to active pursuits. The natural geothermal landscape of the Long Valley area, with its steaming vents, silica-encrusted travertines, and turquoise hot pools set against snow-capped volcanic peaks, creates one of California's most geologically dramatic natural bathing environments.