The trailhead for Sonoma Mountain is located in Jack London State Historic Park
. This state park is located south of Highway 12 between Sonoma and Santa Rosa. The intersection is well marked and signaled for the quaint little town of Glen Ellen and Jack London State Historic Park. Turn south towards Glen Ellen which is .9 mile from Hwy 12. In the middle of town there is a signed right turn to the Jack London State Historic Park. Drive up this road 1.2 miles to the entrance to the park. Pay your $6 day use fee and pull into the large parking lot on the right. This is the trailhead and the elevation here is about 715 ft.
The entrance fee allows you to view the grounds and house also. Hours of entry are 9:30 AM until Sunset.
Mountain Bikers often use the trail system all the way to the highpoint of the park.
The Sonoma Mountain summit is easy to find by following the main trail through Jack London State Historic Park. The main trail starts near the large sign with map in on the south side of the parking lot. The trail starts off as the Lake Trail, passes a picnic area and then a few old farm buildings. When you reach the vineyard, follow the road around the vineyard by first going right, then left and again left
By now you are on the back side of the vineyard and you come to a fork with the Lake Trail going in both directions. Stay to the left on the main road because it is better footing. Follow this road up to the little picturesque lake.
Pass the lake on the left side (you can walk across the dam itself if you want). The trail continues on the far side of the lake and makes a few switch backs as it climbs up Sonoma Mountain. The trail passed through some groves of redwoods and it is a pretty hike.
Continue on the main road. Ignore all branches off the road including the one to Sonoma Ridge. As you climb you will get a few glimpses back at the valley behind you and the forest eventually thins out into grassy meadows. Continue climbing and following the signs for the Mountain Trail or the Park Summit.
Near the summit the area is more open grassland and there is s fork with one going to Hayfield Meadows and the other goes to the left and the park summit. Go left and continue following the road. The road seems to die out in a little basin shortly before the park summit, but a climber’s trail continues to the right. There is a barb wire fence on the left here and the trail parallels the fence as it climbs up to the park summit. The park summit is next to the fence up on the ridge.
From this location you can see several communication buildings and antenna’s about .25 mile across a grassy field. To the left of this communication facility is the highpoint summit of Sonoma Mountain. Climb over the fence and walk straight across the field to the obvious highpoint on the horizon. It is only about .35 of a mile with little elevation gain to get to the summit.
The summit is marked with a large pile of rocks in the middle of a grassy field. This entire hike is about 8.6 miles with about 1,900 ft of elevation gain. It took me 3.0 hours roundtrip.
Mountain Bikers often use the road for access to the park summit.
When hiking, the ten essentials are always required. No technical gear is required. Be sure to bring water. Take your camera and enjoy the views. Take raingear if it is cloudy at all.