Las Trampas Wilderness Regional Preserve

Geology

Two major Bay Area faults--the Las Trampas and Bollinger faults--account for the uplift and exposure of four well-defined geological formations. The Orinda formation holds remnants of ancient beach and shoreline; the El Sobrante formation consists of several fossil-bearing compressed rock layers, and the Pinole Tuff is of volcanic origin.

Little Hills Picnic Ranch

Adjacent to Las Trampas, this facility is available by reservation for group picnics of between 50 and 1,400 people. For information, please see our Little Hills page.

Las Trampas Stables

Las Trampas Stables offers horse boarding, and riding lessons for adults and children. For information call (925) 837-2439.

The O'Neill National Historic Site

Join East Bay Regional Park District Naturalists and National Park Service Rangers on an interactive virtual hike from the town of Danville, along the Iron Horse Trail, into Las Trampas, and finishing at the Tao House at the Eugene O'Neill National Historic Site.

• Download: Virtual Hike Guide [PDF] 

Owned and operated by the National Park Service, this site is open to the public by reservation. Call (925) 838-0249 for information. More information: Eugeneoneill.org

Vegetation

The dominant woodland vegetation on the western and southern exposures of Las Trampas and Rocky ridges is black sage, chamise and buck brush. These are interspersed with toyon, hybrid manzanitas, elderberry, gooseberry, chaparral currant, sticky monkeyflower, coffeeberry, coyote bush, poison oak, hollyleaf red berry, deer weed and dozens of other species. There is some creek dogwood along Bollinger Creek.

The dominant trees are coast live oak and bay laurel. Other species are buckeye, big leaf maple, canyon live oak, black oak and scrub oak. The latter, with its mistletoe, seems to prefer the ridgetop habitat at the end of Chamise Trail. Half a dozen fern species are found in the park and there are large areas of grassland.

Animals and Birds

The park's abundant wildlife includes raccoons, foxes, opossums, bobcats, skunks, and squirrels. Late in the day, with binoculars, you can count the deer in the hill areas adjacent to the parking lot. Las Trampas is Spanish for "The Traps" or "The Snares." According to Erwin G. Gudde's California Place Names, traps were once set in the chaparral of the hills to catch elk. Historical records also indicate that antelope and mountain lions were plentiful during the last century. Sightings of the big cats have been reported in recent years. There are many species of hawks, and golden eagles are occasionally sighted.

The East Bay Regional Park District leases some of the grassland areas for cattle grazing. Cattle keep the grass height down, which lessens the fire hazard during the dry season.

Hiking and Horseback Riding

The park is bisected by Bollinger Creek. To the west is Rocky Ridge, accessible from the parking lot via a paved road that brings hikers near the 2,024-foot summit. At the 1,760-foot elevation, you can hike westward along a trail managed by the East Bay Municipal Utility District to the Valle Vista Staging Area on Canyon Road in Moraga, or south to the Chabot staging area in Castro Valley. A permit is required for hiking on EBMUD lands. Call (510) 287-0459 for more information.

Stone outcroppings on Rocky Ridge are beautifully sculptured by the wind and colored by many lichen species. An entire day may be spent hiking the ridge and the Devil's Hole area. Wildflowers abound in season and are especially beautiful after a rain.

Las Trampas Ridge, reached via Chamise and Bollinger Creek Loop trails, is east of Bollinger Creek. The view from the ridge affords the sights of the Ygnacio, San Ramon and Amador valleys, Mt. Diablo, Carquinez Straits and other distant points of interest. The Corduroy Hills Trail, skirting Eagle Peak, is for hiking only, as are the Sycamore, Mahogany and Trapline trails. Boots are recommended. Park visitors should use only signed trails that appear on the map; trails that do not appear on the map are not maintained by Regional Park staff, and some may be in a sensitive resource area.

Picnicking

Near the parking lot are two picnic areas--Steelhead and Shady. Facilities are available on a first-come, first-served basis. The Little Hills Picnic Ranch is available for group picnics of between 50 and 1,000 people. For reservations, contact The Ranch, at Little Hills at (925) 837-8158, or visit the Little Hills page.

Group Camping

The Corral Area is a reservable overnight group camp. Campers need to provide their own water. The park's water supply is inconsistent and water may be unavailable at any time. For information or reservations phone 1-888-EBPARKS or 1-888-327-2757, press option 2.

Birdwatching

The park is a good place for birdwatching. There are many species of hawks, and golden eagles are occasionally sighted.

Biking

Bicycles may be ridden on designated bicycle trails, and on fire or service roads unless otherwise posted. No bicycles are allowed on Rocky Ridge View Trail.