High Rock Spring

Lassen County, California · Near Janesville
40.2450°N, 120.0070°W · 4,040 ft
86°F 44°F air · Good soaking weather 4,040 ft Short Walk Camping nearby (18.8 mi)
Aerial view of the ground around High Rock Spring LiDAR bare-earth view of the same ground around High Rock Spring
Aerial LiDAR bare earth

Drag the handle to compare the two views. The orange dot marks the spring, in a frame about three quarters of a mile wide.

A warm spring in Lassen County, High Rock sits roughly 26 miles out from Janesville in dry country. The water is tepid, comfortable enough in summer heat and too cool for a winter soak. The USGS keeps a site number for it. Nothing in the record names a land owner, and public access has not been logged. No photo exists.

Location

You park and walk about five hundred feet. That is all the record says about the approach, and it gives no road name. Snowfall is light for the region and annual rain is meagre, so expect dry ground most of the year. The spot sits around four thousand feet, with no land unit listed.

Black Mountain Lookout is the nearest campground on file, nearly nineteen miles off. Winter months score highest on the best-months list. With water this cool, a hot day suits it better than a cold one. Check land status before you go; none is recorded here.

Terrain

Aircraft with laser scanners measured this ground to within inches. The scan strips out trees and buildings, leaving the bare shape of the land around High Rock Spring.

Setting
Open ground
Flat, open ground all around.
Highest ground nearby
29 ft above the spring
Within a quarter mile, to the northeast
Cross-section through the spring

A slice through the ground from south to north, about 0.6 miles end to end.

Elevation data: USGS 3D Elevation Program. Aerial imagery: USGS The National Map. Public domain.

Heat Below
79 milliwatts per square meter of heat flow

That's close to the US average of 65. It's higher than at 14% of the springs on this site.

Heat flow measures the warmth working its way up through the ground from deep inside the earth. Where it runs high, rain and snowmelt that seep down through cracks in the rock come back up hot.

Heat flow estimate: Stanford Thermal Earth Model (Aljubran & Horne, 2024), CC BY 4.0.

Monthly Climate
34°
Jan
37°
Feb
43°
Mar
51°
Apr
60°
May
71°
Jun
79°
Jul
77°
Aug
69°
Sep
55°
Oct
42°
Nov
33°
Dec
Annual Precip: 13.3 in Annual Snow: 28.1 in
Best Time to Visit
December Air 33°F · Water 86°F · +53° contrast
January Air 34°F · Water 86°F · +52° contrast
February Air 37°F · Water 86°F · +49° contrast
December offers 46°F more contrast than July
Current Conditions
44°F
SSE 7.2 mph 50% Good soaking weather
Tuesday 84° Low 47° Sunny
Spring is +2° warmer
Wednesday 78° Low 49° Sunny 3% precip
Spring is +8° warmer
Thursday 76° Low 48° Sunny
Spring is +10° warmer
Friday 79° Low 49° Sunny
Spring is +7° warmer
Saturday 83° Low 51° Sunny
Spring is +3° warmer
Nearby Camping
Nearby Camping
Black Mountain Lookout 18.8 mi away

Overview Black Mountain Lookout remained closed for the 2020 season and is expected to remain closed into 2021. Closure is due to COVID related demands in maintaining a safe environment for our customers and our staff. Black Mountain Lookout is located on the eastern edge of the Beckwourth Ranger District, 10 miles from Highway 395, near Milford, California. The lookout was constructed in 1934 and is a great example of Civilian Conservation Corps (CCC) architecture. The C-3-type lookout is si...

Reservable Yes
Reserve on Recreation.gov →
Temperature
86°F
Warm Hot Boiling
Water Temp 86°F (30°C)
Avg Air Temp 54°F
Above Ambient +32°F
Mild soaking conditions September
Access
Road Access Short Walk
Distance to Road 0.1 mi
Frequently Asked Questions
What is the water temperature at High Rock Spring?
High Rock Spring has a water temperature of 86°F (30°C). This is a warm thermal spring.
Where is High Rock Spring located?
High Rock Spring is located in Lassen County, California at 4,040 feet elevation, near Janesville. Coordinates: 40.2450°N, 120.0070°W.
How do I get to High Rock Spring?
High Rock Spring has Short Walk road access (0.1 mi from the road).
Can I camp near High Rock Spring?
Yes, Black Mountain Lookout is located nearby (18.8 miles away).
Sources: USGS NWIS