The 10, 571 acre Sanhedrin Wilderness was established in 2006 by Public Law 109-362, the Northern California Coastal Wild Heritage Wilderness Act. The Great Sanhedrin was the supreme council of the ancient Hebrews and the imposing ridge that crowns this Wilderness was named after that high council. The terrain in this area is moderately steep and rugged. The Wilderness is managed by the Forest Service, but includes areas of private land.
Elevations in the Wilderness vary from 6,175 feet at Big Signal peak to 1,600 along Thomas Creek. The major creeks in the area drain westward to the Eel River. Soils are moderately to highly erodible, and an unstable fault zone transects the Rocky Point-Ascherman Ranch area.
Trails in the Sanhedrin
Developed trails do not exist within the Sanhedrin at this time, providing a truly untrammeled Wilderness experience. The only public access point for this area is by the lookout on Big Signal Peak at the end of Forest Road 20N04. From this location, visitors can enjoy off trail hunting, hiking, and camping activities.
Although you may come across an old road or cattle trail while visiting the Sanhedrin, no managed trails existed upon designation of the Wilderness. Employees and wilderness stewardship volunteers have begun to identify potential opportunities to designate and maintain foot and horse trails in the Sanhedrin for future use and enjoyment.
We recommend that when visiting the area you bring the U.S. Geological Survey (USGS) 7.5-minute topographic maps that cover the region: USGS maps for the Sanhedrin Wilderness include Sanhedrin Mountain, Brushy Mountain, Foster Mountain, and Van Arsdale Reservoir. PDF MAP »
At a Glance
||You must obtain a California Campfire Permit if you plan to build a campfire or use a stove, unless you are in a developed recreation area (campground or picnic area).
Permits are available free-of-charge at offices of the Forest Service, the Bureau of Land Management, and the California Department of Forestry and Fire Protection.
||January - December
||Individual Use Permits are not required to enter the Wilderness areas on the Mendocino National Forest, although we suggest you sign in at the trail heads. Also check with the nearest Ranger Station before going, to obtain current information and weather conditions on the area. Maximum group size is 25 people/25 stock animals.
Wilderness travel is limited to foot or horseback - NO gliders, bicycles, motorized vehicles, or mechanized equipment of any kind are allowed within the wilderness areas. Wheelchairs are allowed.
||Gas and Groceries available in Upper Lake, CA.
Nearest Medical - East Lakeport, CA.
||Upper Lake Ranger District
Forests consist primarily of Shasta red fir, white fire, Jeffrey pine, sugar pine, ponderosa pine, Douglas-fir and incense cedar. Drier slopes and less fertile soils support chaparral thickets and a variety of hardwoods, including madrone and black oak. Several large glades (dry meadows) are present within the Wilderness. The area also contains extensive areas of nutrient-poor, blue-green and sometimes red serpentine soil that is so inhospitable to many plants that only specially adapted species can survive. As a result, the Sanhedrin Wilderness provides habitat for at least five rare and unique plant species, including the Anthony Peak lupine, which grows only in the Mendocino National Forest.
The Sanhedrin Wilderness is home to the threatened northern spotted owl. The area contains substantial acreages of suitable nesting and denning habitat for the northern spotted owl, marten, fisher, and goshawk. Reproduction of spotted owl and goshawk has been documented in remnant patches of mature forest which survived the Mendenhall fire of 1987. Both Whitney and Thomas Creeks support resident trout and threatened steelhead. Black bear, deer, and mountain lions are also residents of the Wilderness.
Good drinking water is scarce in the Sanhedrin Wilderness. Although streams may look inviting and harmless, they may not be safe sources for drinking water. Many of the area’s waters contain Giardia lambia, a microscopic organism which, when ingested, can cause nausea, abdominal cramps, flatulence, lethargy, diarrhea, and weight loss. Giardia can be readily transmitted between humans and animals. Feces (human or animal waste) can contain the disease; waste should be buried 6 to 8 inches deep and at least 100 feet away from natural waters.
Treat all water for drinking and cooking by either processing through a portable water filter or by boiling over a portable cook stove for 3 to 5 minutes.
IF YOU GET LOST OR INJURED
If you get lost, stay calm and try to remember how you got to your present location. Look for familiar landmarks, trails, or streams. If you are injured, near exhaustion, or it’s dark, stay where you are; someone may be looking for you. If you decide to go on, travel slowly. Try to find a high point with a good view and then plan your route of travel. When you find a trail, stay on it. If you stay lost, follow a drainage downstream. If a person in your party gets injured, treat the injury if you can and make the victim comfortable. Send or signal for help. If you must go for help, leave one person with the injured and do not move until help arrives unless there is more danger in remaining where you are.