Unnamed Thermal Spring

Mono County County, California · Near Mammoth Lakes
37.8360°N, 119.0160°W · 8,159 ft
97°F 8,159 ft Open Short Walk US Forest Service Camping nearby (4.2 mi)

This 97-degree thermal spring sits at 8,159 feet elevation within Inyo National Forest, running an extraordinary 56.7 degrees above the frigid ambient air that averages just 40.3 degrees annually. Among California's hottest thermal springs, this location combines extreme elevation with extreme thermal heating, creating a remarkable high-country thermal experience.

The spring emerges through forests of whitebark pine and mountain hemlock at an exceptionally high elevation where summer lasts only briefly. Steaming thermal water rises from rocky ground amid dense alpine vegetation, surrounded by views of snow-capped peaks. The 535-meter walk to the spring passes through pristine high-country forest largely untouched by development.

History of This Spring

The spring flows on U.S. Forest Service land within Inyo National Forest, where multiple-use management balances recreation and resource extraction. The exceptional temperature results from proximity to active geothermal systems in this volcanically active region where the Long Valley Caldera system extends eastward beneath Mono Basin.

The spring requires a 535-meter walk from vehicle access through potentially snow-covered terrain, making winter visits extremely challenging or impossible. Summer and early fall offer the only practical access windows. Bring warm layers despite the hot spring water, as wind chill and thin alpine air create rapid heat loss. Altitude acclimatization may be necessary at 8,159 feet.

Is this spring worth visiting?

Best for

  • Warm-water soaking
  • Overnight camping trips
This spring is well suited for warm-water soaking and overnight camping trips.
Monthly Climate
24°
Jan
23°
Feb
28°
Mar
34°
Apr
42°
May
55°
Jun
63°
Jul
61°
Aug
55°
Sep
44°
Oct
32°
Nov
22°
Dec
Annual Precip: 22.1 in Annual Snow: 130.0 in
Best Time to Visit
December Air 22°F · Water 97°F · +75° contrast
February Air 23°F · Water 97°F · +74° contrast
January Air 24°F · Water 97°F · +73° contrast
December offers 40°F more contrast than July
Nearby Camping
Oh Ridge 4.2 mi away

Overview The outstanding lake and mountain views at Oh Ridge Campground make it a favorite spot for both families and anglers. It sits in the eastern Sierra Nevada Mountains in close proximity to the Ansel Adams Wilderness, Yosemite National Park and Mono Lake. The nearby town of June Lake offers the convenience of shopping and dining, while the surrounding land and lakes provide ample outdoor recreation opportunities.Recreation Oh Ridge campers have no problem staying busy and enjoying the o...

Reservable Yes
Reserve on Recreation.gov →
What to Bring
Swimsuit & towel
Water bottle Stay hydrated, especially in hot water
Warm layers Cold air before and after soaking
Camping gear Nearby camping at Oh Ridge
Trash bag Pack out what you pack in
References
USGS Quad: (MONO CRATERS 15) · NOAA: 4.0 · AMS Map: MARIPOSA
Frequently Asked Questions
What is the water temperature at ?
has a water temperature of 97°F (36°C). This is a warm thermal spring.
Where is located?
is located in Mono County, California at 8,159 feet elevation, near Mammoth Lakes. Coordinates: 37.8360°N, 119.0160°W.
How do I get to ?
has Short Walk road access (0.3 mi from the road).
Is free to visit?
has Open access. It is managed by US Forest Service.
Can I camp near ?
Yes, Oh Ridge is located nearby (4.2 miles away).
Is it safe to soak at ?
is generally safe for soaking at its recorded temperature. 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, warm layers for before and after soaking, camping gear, a trash bag to pack out what you pack in.
Temperature
97°F
Warm Hot Boiling
Water Temp 97°F (36°C)
Avg Air Temp 40°F
Above Ambient +57°F
Perfect soaking weather March
Access
Open
Road Access Short Walk
Distance to Road 0.3 mi
Land
Ownership Federal
Agency US Forest Service
Designation National Forest
Unit Inyo National Forest
Manager US Forest Service
Protection 3 - Protected, subject to extractive use