Location and surroundings
Geographically part of the North American Cordillera, Cobb Mountain sits within the Pacific Coast Ranges, specifically the California Coast Ranges and the Northern California Coast Ranges, before reaching its home range in the Mayacmas Mountains. It is the highest of 49 named peaks in the Mayacmas Mountains within United States, located in the district of Lake County in California.
The surrounding landscape features isolated small valleys and basins between the mountain peaks of the Cobb Mountain Area, many of which share a volcanic origin with nearby elevations like Boggs Mountain, Mount Hannah, and Seigler Mountain. Slopes of the peak drain into various local waterways, including Putah Creek, Anderson Creek, Cobb Creek, Big Sulphur Creek, Alder Creek, and Kelsey Creek.
Neighbouring peaks
Cobb Mountain is closely surrounded by several other elevations in the region. The nearest peaks and passes include:
- Burned Mountain (peak), 905 m, 3.1 km SW
- Boggs Mountain (peak), 1,139 m, 5.2 km E
- Castle Rock (peak), 804 m, 7.2 km S
- Seigler Mountain (peak), 1,108 m, 7.9 km N
- Harbin Mountain (peak), 785 m, 8.3 km E
- Red Hill (peak), 768 m, 8.8 km S
- Mount Hannah (peak), 1,213 m, 8.9 km N
- Pine Mountain (peak), 1,091 m, 8.9 km S
As the highest point among these local summits and across the Mayacmas Mountains, Cobb Mountain exceeds the elevations of all its immediate neighbours.
The view from the summit
From the higher elevations of Cobb Mountain, including its sub-peak Cobb Mountain – Southwest Peak, hikers and observers can look out across the surrounding region. The highest peaks visible within a 25 km radius include Mount Saint Helena at 1,319 m situated 17.9 km SE, Wright Peak at 1,310 m located 18.7 km N, and Mount Saint Helena South Peak at 1,220 m at 19.9 km SE.
Further prominent points in the broader surrounding area include Mahnke Peak at 1,085 m lying 11.6 km NW, Geyser Peak at 1,053 m located 10.2 km SW, and Monument Peak at 1,001 m sitting 21.9 km NW. On clear days, distant taller summits such as Snow Mountain can also be spotted from the southern portions of the mountain.
The range
The mountain range hierarchy places Cobb Mountain within the North American Cordillera, progressing down through the Pacific Coast Ranges, the California Coast Ranges, and the Northern California Coast Ranges, terminating in the Mayacmas Mountains. The Mayacmas Mountains contain 49 named peaks in total.
Cobb Mountain stands as the highest point of the Mayacmas Mountains. A sub-peak, Cobb Mountain – Southwest Peak, also serves as the highest point in Sonoma County along the Sonoma-Lake county line.
Access and starting points
The nearest settlement to Cobb Mountain is the town of Cobb, located 2.2 km NE of the main summit. Much of the mountain lies within The Geysers Geothermal Field, while other areas are owned by Cobb Mountain Spring Water or function as privately held timberlands. Because large portions of the terrain are privately owned, access for the general public is largely restricted.
OpenStreetMap data records ten mobile phone and communication masts mapped within 10 km of the summit, with the nearest positioned 80 m S. Walking times from the town of Cobb, starting from about 800 m elevation over roughly 2.9 km on foot with 640 m of height gain, are estimated via Naismith's rule to take around 1.5 to 2 hours.
Climate and weather
Climate estimates derived from NASA POWER data covering 2001 to 2020 provide monthly means adjusted to the summit elevation of Cobb Mountain. The warmest month at the summit is July with an average temperature of about 20 °C, while January is the coldest month with a mean of about 3 °C.
Mean temperatures remain above freezing at the summit throughout all twelve months of the year. Precipitation in the surrounding area averages about 750 mm annually, with December experiencing the wettest conditions at about 170 mm and July representing the driest month with about 0 mm of precipitation.
Best time to visit
Based on temperature data, the summit maintains mean temperatures above freezing during every month from January through December. However, drier conditions occur during the summer months, with July receiving virtually no precipitation, whereas winter months bring significantly higher rainfall totals.
Because the mountain experiences winter snowfall similar to nearby Mount Saint Helena, visitors typically plan ascents during drier periods when weather hazards related to winter storms and wet terrain are minimized.
Nature and wildlife
The landscape around Cobb Mountain features forested terrain, including privately held timberlands, interspersed with small valleys and basins. Volcanic origins characterize many elevations in the Cobb Mountain Area, influencing local geological formations and hydrology.
The vegetation reflects the Mediterranean climate of the Northern California Coast Ranges, supporting diverse plant communities adapted to seasonal precipitation patterns and variable elevations across Lake County and Sonoma County.
Guides and organised ascents
For visitors seeking organized ascents or professional instruction in United States, national representation is provided by the American Mountain Guides Association, which is a member of the IFMGA/UIAGM, alongside the American Alpine Club as the national mountaineering federation.
Established guiding companies operating within the country include RMI Expeditions based in Ashford, Washington, and Exum Mountain Guides located in Moose, Wyoming. Climbers should also note national permit rules, as certain peaks in United States require climbing registration or permits from the relevant land agency, such as advance registration for Denali or specific permits for Mount Rainier.
Safety and preparation
Ascents in the region require appropriate preparation for changing weather conditions, elevation gains, and navigating private lands. Hikers should ensure they carry adequate water, especially during the dry summer months when precipitation drops to near zero.
In the event of an emergency, the general emergency number across United States is 911. Dispatchers will alert the local search and rescue team, which is typically managed by the county sheriff or national park authorities.
History and name
The mountain derives its name from John Cobb, the first pioneer to settle in the area. Born in Henry County, Kentucky on May 19, 1814, John Cobb arrived in California in 1853 and homesteaded in Cobb Valley. He later served as county assessor and road overseer for the Clearlake District in 1855, and built a combined saw and gristmill in 1859 before moving to Napa County around 1860.
In 2015, the area experienced severe devastation from the Valley Fire, which burned 76,000 acres, destroyed parts of the town of Cobb and several geothermal facilities, and became the third-most destructive fire in California history. The fire started on Cobb Mountain due to faulty hot tub wiring.
Interesting facts
Cobb Mountain holds the distinction of being the highest of 49 named peaks in the Mayacmas Mountains. Furthermore, its sub-peak, Cobb Mountain – Southwest Peak, serves as the highest point in Sonoma County.
Much of the mountain is situated within The Geysers Geothermal Field, and commercial operations have historically bottled spring water from the mountain, formerly sold as Cobb Mountain Spring Water and presently marketed as Mayacamas Mountain Spring Water.
FAQ
What is the elevation of Cobb Mountain? Cobb Mountain reaches an elevation of 1,440 m.
Where is Cobb Mountain located? Cobb Mountain is located in the United States, within the state of California and Lake County, forming the highest point of the Mayacmas Mountains.
What range does Cobb Mountain belong to? It belongs to the Mayacmas Mountains, part of the Northern California Coast Ranges, California Coast Ranges, Pacific Coast Ranges, and the North American Cordillera.
What are the nearest peaks to Cobb Mountain? The nearest peaks include Burned Mountain at 905 m (3.1 km SW), Boggs Mountain at 1,139 m (5.2 km E), and Seigler Mountain at 1,108 m (7.9 km N).
Is there water on the way to Cobb Mountain? 5 to 3 liters of water depending on conditions since public access is limited and natural sources should be treated.
Are there huts on Cobb Mountain? OpenStreetMap shows no mountain huts or shelters directly on Cobb Mountain, so hikers generally plan ascents as day trips.
How long does it take to walk up Cobb Mountain? Walking from the town of Cobb (2.2 km NE, starting around 800 m elevation over a 2.9 km distance with 640 m of height gain) is estimated by Naismith's rule to take roughly 1.5 to 2 hours.
What is the mobile phone coverage on Cobb Mountain? OpenStreetMap maps ten communication masts within 10 km, with the nearest 80 m S, suggesting signal is likely near masts or open summits, though maps should be downloaded offline and 112 or 911 can reach emergency services over any available network.