Unnamed Thermal Spring

Solano County County, California · Near Benicia
38.1010°N, 122.1690°W · 218 ft
73°F 218 ft Roadside Camping nearby (24.5 mi)

Near Benicia in Solano County, this 73-degree spring flows at 218 feet, 14 degrees warmer than ambient, just 68.5 meters from Lake Herman Road overlooking the Carquinez Strait.

The short walk from Lake Herman Road crosses grassland sloping toward the strait where the Sacramento and San Joaquin Rivers merge their waters on the journey to the Pacific. The spring emerges in rolling terrain of golden grass and scattered oak. Views extend to the water where maritime traffic passes between the Central Valley and San Francisco Bay. The setting combines hill country with proximity to major waterways.

History of This Spring

The Carquinez Strait marks a critical geological boundary where major faults separate the Coast Ranges from the Sacramento Valley. This thermal spring reflects heat from deep crustal processes active along these fault zones. The area has supported human settlement from Native American peoples through Spanish colonial periods and into the modern industrial era.

This spring's convenient roadside location requires minimal walking effort. Year-round access is available, though autumn and spring offer the most pleasant conditions. The proximity to Lake Herman creates opportunities to combine water recreation with spring visitation. Nearby Benicia offers dining and amenities.

Is this spring worth visiting?

Best for

  • Easy day trips
  • Overnight camping trips
This spring is well suited for easy day trips and overnight camping trips.
Monthly Climate
49°
Jan
51°
Feb
54°
Mar
58°
Apr
62°
May
67°
Jun
67°
Jul
68°
Aug
68°
Sep
64°
Oct
55°
Nov
49°
Dec
Annual Precip: 18.4 in Annual Snow: 0.0 in
Best Time to Visit
January Air 49°F · Water 73°F · +24° contrast
December Air 49°F · Water 73°F · +24° contrast
February Air 51°F · Water 73°F · +22° contrast
January offers 19°F more contrast than September
Nearby Camping
Aquatic Park Cove, Black Point Overnight Anchoring, Sailing Vessels Only (Auxiliary Engine Ok) 24.5 mi away

Overview Aquatic Park Cove is a vibrantly urban harbor that mimics a natural anchorage and is located on the Pacific shores of one of America's great West Coast cities. San Francisco Maritime National Historical Park's Aquatic Park Cove is the small craft gateway to San Francisco. Vessels entering Aquatic Park Cove are instructed to contact the Park's permit officer on VHF marine radio channel 83A (157.175Mhz) using the call sign "Aquatic Park NPS" followed by transmission of the vessel'...

Reservable Yes
Reserve on Recreation.gov →
What to Bring
Swimsuit & towel
Water bottle Stay hydrated, especially in hot water
Camping gear Nearby camping at Aquatic Park Cove, Black Point Overnight Anchoring, Sailing Vessels Only (Auxiliary Engine Ok)
Trash bag Pack out what you pack in
References
USGS Quad: (BENICIA 7.5) · NOAA: 41.0 · AMS Map: SANTA ROSA
Frequently Asked Questions
What is the water temperature at ?
has a water temperature of 73°F (23°C). This is a warm thermal spring.
Where is located?
is located in Solano County, California at 218 feet elevation, near Benicia. Coordinates: 38.1010°N, 122.1690°W.
How do I get to ?
has Roadside road access, with the nearest road being Lake Herman Road (225 ft from the road).
Can I camp near ?
Yes, Aquatic Park Cove, Black Point Overnight Anchoring, Sailing Vessels Only (Auxiliary Engine Ok) is located nearby (24.5 miles away).
Is it safe to soak at ?
is generally safe for soaking at its recorded temperature. 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?
is accessible from a paved road, making it easy to reach. Weekends and holidays may be busier — consider visiting on a weekday for a quieter experience.
What should I bring to ?
Essentials for : swimsuit, towel, water bottle, camping gear, a trash bag to pack out what you pack in.
Temperature
73°F
Warm Hot Boiling
Water Temp 73°F (23°C)
Avg Air Temp 59°F
Above Ambient +14°F
Mild soaking conditions March
Access
Road Access Roadside
Nearest Road Lake Herman Road
Distance to Road 225 ft