Much of the information posted here can be attributed to Yolohiker.org. Be sure to visit for more information on Glascock and other Cache Creek hikes.
Glascock Mountain lies along the Cortina Ridge on the boundry of Yolo and Colusa counties. The Cortina Ridge is a continuation of the Blue Ridge located to the south, however Cache Creek has cut a 2,000 ft canyon between them. Glascock stands about 2,000 feet above the creek to the north. Glasscock is the southern most highpoint on the Cortina Ridge.
The peak hiking possibilities of the Cache Creek area are fantastic. The area is as close to wilderness as you can come near the Bay Area.
Thanks to fire activity over the years, most routes to the summit are along old fire breaks. If one strays from the breaks however, the bushwacking becomes intense. Dense new growth is reappearing, but much of the burnt out manzanitas are still standing and can be extremely difficult to negotiate.
There are at least two directions to approach the summit. The shortest (2 miles one way, 2,000 ft gain) is from the southeast and requires more elevation gain than the longer approach. The longer approach from the northwest is approximately 5 miles one way with about 1,700 ft of elevation gain.
From the Bay Area: Take I-80 east to Reno. In Vacaville, turn north on I-505. Continue to Hwy 16, west of Woodland. Go west on Hwy 16 for approximately 27 miles. The road narrows and is on the south side of the creek. The Cache Creek bridge takes the road to the north side of the creek. The parking area is just beyond the bridge on the right.
From Sacramento: Take I-5 north to Woodland. Exit on Main Street. Main Street becomes Hwy 16. Continue on Hwy 16 until I-505 is reached. Follow directions above.
Follow above directions, but travel an additional 5 miles past the Cache Creek Bridge to the parking area. Parking is located on the creek side of the road. The trailhead is located at a locked gate (you'll have to hop it) about 100 yards further along the road.
Glascock Mountain lies within BLM lands in the Cache Creek Natural area, and as such there are few restrictions on use. It is a primitive area, closed to motorized vehicles. There are no developed campgrounds or facilities. Non-hunting (target) shooting is not allowed. There are no use fees for hiking, biking or riding. There are no parking fees. Campfire permits are required.
The following link takes you to the BLM Cache Creek site with additional information: