Cobb Mountain's main summit The mountain has a sub-peak referred to as
Cobb Mountain – Southwest Peak with an elevation of about 4483+ feet, (1367+ m); Southwest Peak lies on the
Sonoma-Lake county line and is the highest point in Sonoma County. Nearby taller peaks like Mount Saint Helena and
Snow Mountain can be seen from this summit. Cobb Mountain is one of the mountains in the Cobb Mountain Area, many of which have volcanic origin. Others are
Boggs Mountain,
Mount Hannah and
Seigler Mountain. There are isolated small valleys and basins between the mountain peaks. The east end of Cobb Mountain drains into the headwaters of
Putah Creek, then into the
Sacramento River, the
San Francisco Bay, and the
Pacific Ocean. The south slopes of Cobb Mountain drain into Anderson Creek, and thence into Putah Creek. The southwest slopes of Cobb Mountain drain into Cobb Creek, thence into
Big Sulphur Creek, the
Russian River, and into the Pacific. The northwest slopes of Cobb Mountain drain into Alder Creek, thence into
Kelsey Creek,
Clear Lake,
Cache Creek, and the Sacramento River. The northeast slopes of Cobb Mountain drain into Kelsey Creek. Much of Cobb Mountain lies within
The Geysers Geothermal Field, and several geothermal plants are located on the mountain. Other areas on the mountain are owned by Cobb Mountain Spring Water (now sold as Mayacamas Mountain Spring Water) or are privately held timberlands. Because much of Cobb Mountain is privately owned, it is largely not accessible to the general public. == History ==