Unnamed Thermal Spring
This 81-degree thermal spring emerges just 83.5 meters from Old Long Valley Road near Clearlake, warming the water 19.7 degrees above ambient temperatures in Lake County's temperate foothill climate. The modest heat gain reflects the transition between hot coastal influences and cooler inland conditions.
The spring rises at 1,428 feet elevation in rolling oak woodland terrain with scattered madrone and manzanita. Warm water trickles from the thermal source into shallow pools surrounded by native plants and sun-exposed rock. The nearby road brings the sound of occasional traffic but also easy vehicle access.
This spring lies in the Mayacamas Range foothills where volcanic basement rocks underlie younger sedimentary deposits. Lake County's geothermal resources remain largely undeveloped, in contrast to Napa County's intensive exploitation just to the west, reflecting different land use priorities and geological complexity.
The location provides roadside access with minimal walking distance. The landscape offers warm pools suitable for soaking during cooler months. Summer temperatures reach into the 80s, reducing the spring's relative warmth, so autumn and winter visits offer the most dramatic thermal contrast.
Is this spring worth visiting?
Best for
- Warm-water soaking
- Easy day trips
- Overnight camping trips
Overview This location is available on a first-come, first-served basis only. Visitors are required to physically arrive at the campground to purchase and claim a site.Once on-site, you are able to pay for your campsite(s) by scanning a QR code using the Recreation.gov mobile app, and the Scan and Pay feature.In order to utilize Scan & Pay on site, you will need to first download the free Recreation.gov mobile app https://www.recreation.gov/mobile-app prior to your arrival as some remote area...