Unnamed Thermal Spring
Near Lost Hills, this 93-degree spring exceeds ambient temperatures by 26 degrees, creating remarkably hot water in California's western San Joaquin Valley at 1,168 feet elevation.
Approaching the spring, you walk 156 meters through semi-arid grassland and shrubland typical of the southern San Joaquin Valley. The landscape shows the marks of intensive agriculture and energy development. The hot water itself appears clean and clear, surrounded by sparse vegetation adapted to the dry climate. Sunbaked earth radiates heat in summer.
This spring's exceptional heat results from geothermal energy rising through the valley's thick sedimentary layers. The region has been known for oil and gas production for over a century, reflecting the same deep heat sources that warm the spring. Native peoples likely used these warm waters long before modern development transformed the valley.
Spring appears in late fall through early spring. Bring plenty of water as shade is minimal in this exposed landscape. The short walk is straightforward but unshaded. High summer temperatures make visitation uncomfortable. Check local conditions before traveling to this remote location.
Is this spring worth visiting?
Best for
- Warm-water soaking
- Overnight camping trips
Camping is available on a first come-first serve basis. Thirteen campsites with picnic tables, fire pits, horse corrals and a wheelchair accessible vault toilet. Electricity and drinking water is not available. There is no garbage service, please act responsibly and pack out any refuse you have. This campground is more secluded and the camper is only steps away from unlimited hiking in the Wilderness Study Area that lies outside the campground.