Arcadia, CA 91006
- 5 miles round-trip
- 1.5 - 2.5 hours
- Trailhead Elevation:
- 1600 feet
Mt. Williamson affords a spectacular view of the strange rock formations of the Devil’s Punchbowl, as well as part of the famous San Andreas Fault. Both of these geological formations lie directly below and to the north and northwest of Mt. Williamson. The first summit you reach on the faint trail along the ridge (about one-half mile from the main trail) is the one marked on the topographical map. From there you will see another rise on the ridge about one-fourth mile to the northwest and about 30 feet higher. This summit has the best view of Devil’s Punchbowl and the San Andreas Fault.
Mt. Williamson was named for Lt. Robert Williamson of the U.S. Army. In 1853, he led a party looking for a railway route from the desert across the mountains. He located two routes, one over Cajon Pass and the other through Soledad Canyon.
Map + Directions
Follow the Angeles Crest Highway 14 miles beyond Chilao to Islip Saddle, which is at the junction of Angeles Crest and Highway 39. A National Forest Adventure Pass is required for your vehicle while parked in this area. At the western edge of the parking area, take the trail leading uphill in a northwesterly direction. It is a steady climb (1,600 foot elevation gain) with fine views through a forest of Jeffrey, Ponderosa and Sugar Pine, along with some low-growing patches of Ceanothus and Chinquapin. After two miles, a ridge top is reached, with the main trail descending on the other side two more miles to an unnamed saddle on the Angeles Crest Highway (1.6 miles west of Islip Saddle). Leave the main trail at this ridge top, going right on a faint trail up the ridge one-half mile to the summit. Return the same way, or if you can car shuttle, you can go down the trail on the opposite side of the ridge from Islip Saddle to the unnamed saddle just west of the tunnels on the Angeles Crest Highway.