If you know enough about volcanos to expect them to have a characteristic cone shape, you won't find that at Sibley Volcanic Regional Preserve. Over the past 10 million years, nature's forces turned the long-extinct cinder cone on its side, leaving its guts exposed. If you love geology, you will want to check the exhibits and use the self-guided geology trail map to learn more.
But perhaps the best thing about Sibley Volcanic Regional Preserve are the views from its hiking trails. From the park's location on the east side of the San Francisco Bay, you can see Mount Diablo, Mount Tamalpais, and the Golden Gate Bridge. On an exceptionally clear day, you might even catch sight of the Farallon Islands.
The small visitor center at Sibley Preserve is unstaffed. You will find flush toilets and water there, along with some displays about the area's geology and self-guided trail maps. There is no entrance fee.
Hiking and Biking
The park has seven hiking trails, ranging from easy to moderate, each one a few miles long. You can see the trail routes on this map of Sibley and get trail descriptions and ratings at the Hiking Project.
During the rainy season, hike to the pond to see the California newts, shiny, orange-and-black amphibians that come out to mate and lay their eggs. The Pond Trail goes there from the end of the Quarry Trail. If you're taking your dog along, leash them before approaching the water to protect the newts and their babies.
Most of the trails are for people and horses only. Bicycles can go on on the Skyline Trail between the Sibley visitor center and Old Tunnel Road and on wider fire trails and paved roads. You can also camp at the Sibley Backpack Camp; it's a hike-in camp about 0.2 miles from the parking area, with 15 campsites.
The Sibley Labyrinths
East Bay artist and psychic Helena Mazzariello created the first Sibley labyrinth in 1989. To see it, take the Round Top Loop Trail. You can see a second, heart-shaped labyrinth from the Volcanic trail at location Number 5 on the self-guided map.
A labyrinth has only one way in and out, unlike a maze that has many paths. It is designed for thinking and reflection. Walk slowly and respect the silence of others around you. Some people take a small trinket to leave at the center.
You can also take a guided hike to the labyrinth that includes an introduction to the land and grounding meditation. Cannabis is also included as part of the ritual, which is why all hikers must be age 21 or older.
Tips for Visiting Sibley Volcanic Regional Preserve
- If you’re going to Sibley for the views, look up before you leave home to see if the hilltops are stuck in the clouds. And check the weather forecast for foggy conditions. Otherwise, all you may see is a gray mist.
- The park has less than 40 parking spots. To avoid difficulties, get there early on weekends.
- Dogs need to be on a leash on the trail from the visitor center but can run free after you get to the off-leash area.
- Pay attention to the vegetation. Poison oak grows along some of the trails. To recognize it, remember the old saying: “Leaves of three, let it be.”
- You’ll also find foxtails growing along the trails, with bunches of upward-facing spines sticking out from the center like a bushy tail. If the spines and aren't removed and burrow into the skin and soft tissues, they can cause infections. Check your skin for them after your hike. Brush your dog thoroughly and check between their toes, in their nostrils and ear canals.
- Other things to watch out for include snakes and ticks. An occasional mountain lion has been sighted in the park.
- You may find wildflowers in the park during spring and early summer, but don't expect those splashy displays you see in the media.
- Ignore the Google maps location for the labyrinths. It is wrong and will take you to the middle of a neighborhood.
- During the rainy season, the labyrinths may be underwater. And some of the trails get so muddy and slippery that they are almost impassable.