Unnamed Thermal Spring

Lake County, California · Near Cobb
38.7770°N, 122.7630°W · 2,170 ft
120°F 55°F air · Good soaking weather 2,170 ft Short Walk Camping nearby (13.4 mi)

In the Mayacamas Mountains, this exceptional 120-degree spring flows at 2,170 feet, exceeding ambient temperatures by 62 degrees in one of California's premier geothermal regions.

Location

A short 100-meter walk from Big Sulphur Creek Road brings you to intensely hot water surrounded by mixed conifer forest. Redwood and Douglas fir create deep shade along the approach. The spring's vigorous flow and steaming waters create a striking contrast to the cool, wet forest surroundings. The intense heat radiates noticeably as you approach.

The 100-meter walk is moderate and well-defined. Extreme water temperatures—exceeding 240 degrees Fahrenheit—demand caution and respect. Autumn and spring provide the most comfortable visiting conditions in these higher elevations. Winter may bring snow and muddy trail conditions.

History of This Spring

Lake County's geothermal belt includes numerous hot springs, fumaroles, and commercial power plants that harvest Earth's heat. This spring reflects the region's active geological past and present, where magma still heats groundwater in fractured rock. The area has supported human settlement for thousands of years thanks to its thermal resources.

Monthly Climate
45°
Jan
47°
Feb
48°
Mar
53°
Apr
59°
May
69°
Jun
73°
Jul
73°
Aug
69°
Sep
62°
Oct
51°
Nov
45°
Dec
Annual Precip: 34.4 in Annual Snow: 2.0 in
Best Time to Visit
January Air 45°F · Water 120°F · +75° contrast
December Air 45°F · Water 120°F · +75° contrast
February Air 47°F · Water 120°F · +73° contrast
January offers 28°F more contrast than August
Current Conditions
55°F
SSE 10.8 mph 89% Good soaking weather
Today 80° Low 63° Sunny
Spring is +40° warmer
Monday 83° Low 64° Sunny
Spring is +37° warmer
Tuesday 85° Low 65° Sunny
Spring is +35° warmer
Wednesday 86° Low 65° Sunny
Spring is +34° warmer
Thursday 85° Low 63° Sunny
Spring is +35° warmer
Where to Stay

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Nearby Camping
Warm Springs Rec Area 13.4 mi away

Overview Warm Springs Recreation Area is a day-use park located at Lake Sonoma, which is just a 45 minute drive north of Santa Rosa and a 2 hour trip from San Francisco. There is no overnight camping available at this facility World famous vineyards and a land rich in history surround the lake, where visitors enjoy boating, fishing and exploring the area's extensive trail network.Recreation The Woodland Ridge Nature Trail begins at the park and winds up the ridge, rewarding hikers with great...

Reservable Yes
Reserve on Recreation.gov →
Temperature
120°F
Warm Hot Boiling
Water Temp 120°F (49°C)
Avg Air Temp 58°F
Above Ambient +62°F
Great soaking conditions June
Access
Road Access Short Walk
Nearest Road Big Sulphur Creek Road
Distance to Road 328 ft
Frequently Asked Questions
What is the water temperature at ?
has a water temperature of 120°F (49°C). This is considered a hot spring, well above body temperature.
Where is located?
is located in Lake County, California at 2,170 feet elevation, near Cobb. Coordinates: 38.7770°N, 122.7630°W.
How do I get to ?
has Short Walk road access, with the nearest road being Big Sulphur Creek Road (328 ft from the road).
Can I camp near ?
Yes, Warm Springs Rec Area is located nearby (13.4 miles away).
Is it safe to soak at ?
At 120°F, is hot enough to require caution. Enter slowly, limit soaking sessions to 15–20 minutes, and stay hydrated. Access may be on private land or unconfirmed — verify current conditions before visiting. Always tell someone your plans before visiting remote hot springs.
Is crowded?
sees varying levels of visitors depending on the season and day of the week.
What should I bring to ?
Essentials for : swimsuit, towel, water bottle, camping gear, a trash bag to pack out what you pack in. The water is over 110°F — test the temperature before entering and watch for scalding near the source.