Robert Sibley Volcanic Regional Preserve is one of the East Bay Regional Park District's oldest parks. Located in the Oakland Hills just off Skyline Boulevard, Sibley was dedicated in 1936. The most prominent feature in Sibley Park is Round Top, a hill that rises 1,763 feet, and is made up of lava and volcanic debris left over from a small volcanic complex approximately 10 million years old, belonging to the Moraga Formation. After the volcanism ended, tectonic compression across the Hayward and Moraga earthquake faults uplifted the Contra Costa Range, tilting the volcanic complex on its side along with the adjoining formations. 2
Originally called Round Top Park, Sibley shares with Temescal and Tilden the distinction of being one of the East Bay Regional Park District's original parks. The preserve was later named in honor of Robert Sibley, who helped found the District and served for 10 years on its board of directors. 2
From different points in the park, it's possible to see Mount Diablo, Mount Tamalpais, the Golden Gate Bridge, and on a clear day, the Farallon Islands and the Sierra Nevada.
Historically the operations of two large rock quarries were centered in this area. These expose various structures of the volcanic complex as well as the Orinda Formation to its west, accessible by lovely walking trails that are runner, family and dog friendly. The park is also known for its mysterious labyrinths along the base of the quarry canyons. Brochures and maps can be obtained at the visitor's center which map out self-guided tours along the Round Top Loop Trail. 1
You can get to the park via Grizzly Peak Blvd. or Skyline Blvd. On foot, the park is connected to the Bay Ridge Trail and can be reached from Huckleberry Botanic Regional Preserve. You can reach the park by bicycle following either of the roads, but a great way to pedal there is via Tunnel Road to Skyline Blvd. Starting below Hiller Highlands, the road winds up above the Caldecott Tunnel, providing nice views, a fairly easy grade, and few cars. It will also take you past the location of the former Kennedy Tunnel where Tunnel Road becomes Skyline Blvd. If you are not coming from North Oakland, the best bet is probably to take the Montclair Railroad Trail up the hill to Skyline Blvd. For dedicated hikers, two graded dirt roads lead from the private Wilder Ranch development in Orinda into the eastern side of the park. In addition, the McCosker Sub-Area of the park, adjacent to Huckleberry on its south side, is accessible from the Wilcox Station Staging Area on Pinehurst Road.
In the Park
Most trails are hiking and equestrian only. A few trails are multi-use. Dogs are permitted at Sibley, but are not allowed on adjacent Huckleberry trails. A visitor center at the park shelves self-guided tour brochures so guests can stroll the park and learn of its historic significance at their own leisure. 2
Bicycles are not allowed on narrow-gauge trails, except on the Skyline Trail between the Sibley visitor center and Old Tunnel Road. Bicycles are allowed on the wider-gauge fire trails and paved roads, but are not allowed on Round Top Road from the fork .15 mile east of the visitor center to the top of Round Top. 2
Links and References
- Sibley Volcanic Regional Preserve: Labyrinths San Francisco Chronicle
Sibley Volcanic Regional Preserve East Bay Regional Park District
Sibley Volcanic Regional Preserve Hike Embrace the Outdoors
Exploring Sibley Volcanic Regional Preserve KQED Quest July 8, 2008
- Wait, There Was A Volcano in the East Bay Hills? KQED Bay Curious June 3, 2021
Sibley Volcanic Regional Preserve Great Kids Parks