About The Park

In their backyard at Sibley Volcanic Regional Preserve, East Bay residents have a volcano. Originally called Round Top Park, Sibley shares the distinction with Temescal and Tilden of being one of the original parks of the East Bay Regional Park District. Later, the preserve was named in honor of Robert Sibley, who helped found the District and served on its board of directors for 10 years.

Round Top, one of the highest peaks in the region, consists of lava and volcanic debris left over from a 10 million-year-old volcano. Massive tectonic forces on the Hayward and Moraga earthquake faults have uplifted the Berkeley hills over the past 10 million years, folding bedrock formations and tilting the Round Top volcano complex on its side.

From the Orinda Formation, softer sedimentary rock eroded away, exposing the Round Top volcano. In addition, cross-sections of the bedrock geology have been revealed by quarrying in the north half of the preserve, providing an unsurpassed outdoor laboratory for the study of volcanism in the Central Coast Ranges.

Park Features

The most famous feature of the preserve is the Round Top (elevation 1763 ft. above sea level).

At the Skyline Boulevard staging area, the unstaffed visitor center has displays illustrating the geology of the preserve. At the staging area, a self-guided brochure is available which highlights the geological features of the preserve.

Access throughout the preserve is provided by several trails. The National Recreation Trail of the 31-mile East Bay Skyline, part of the Bay Area Ridge Trail system, crosses the preserve between Wildcat Canyon and Anthony Chabot Parks along the ridgeline. From the Sibley visitor center, Round Top Road goes to the top of Round Top. Round Top Loop Round Top peak trail circles. Most of the stops on the self-guided volcano tour are on the Volcanic Trail, once a quarry transport road.

The paved Quarry Road rises from the Old Tunnel Road on the northwest side of the park and meets the east end of the Volcanic Trail. Quarry Trail connects the middle of Volcanic Trail to a point lower down on Quarry Road. Finally, the Pond Trail is a short segment of the trail that descends to a few ponds on the preserve's north side.

Park Activities

The majority of trails are only hiking and equestrian. A couple of trails are multi-use. At Sibley, dogs are permitted but are not permitted on adjacent Huckleberry trails. Self-guided tour brochures for a visitor center at the park shelves so that guests can stroll through the park and learn at their own leisure about its historic significance.

Except on the Skyline Trail between the Sibley visitor center and Old Tunnel Road, bicycles are not permitted on narrow-gauge trails. Bicycles are permitted on the wider-gauge fire paths and paved roads but are not permitted from the fork .15 mile east of the visitor center to the top of Round Top on Round Top Road.

Park Accessibility

Round Top Road is paved to the top of Round Top. There is also a 600-foot, paved wheelchair path north of the visitor center that ends at a viewing platform. (Watch for occasional vehicles using the road.) Also paved is Quarry Road, starting at Old Tunnel Road.

To Reach The Park

Take Fish Ranch Road from Highway 24, immediately east of the Caldecott Tunnel. Continue to Grizzly Peak Boulevard for 0.8 miles. Turn left and follow Grizzly Peak to Skyline Boulevard for 2.4 miles. Turn left and drive .1 mile to the preserve entrance on the left.

AC Transit #305, the closest bus line, runs on Tuesdays and Thursdays only, from mid-morning to mid-afternoon. Take the AC Transit 59 or 59A bus from Lake Merritt BART, 19th Street BART, or Rockridge BART; these bus lines go to the Montclair Transit Center. Transfer to AC Transit bus 305 from there and exit at the Colton Boulevard and Ridgewood Drive stop. Walk the short distance to Skyline Boulevard from Colton, turn left and continue towards the preserve. It is a 0.9-mile walk, mostly level, passing the staging area of the Huckleberry Preserve.