Sandstone climbing spot near Silicon Valley

Climbers have scaled the park's outcrops of vaqueros sandstone at Castle Rock and Goat Rock for nearly a century. The rock's hard exterior — pocked with caves, crevices, bumps and depressions called tafoni patterns — is ideal for bouldering and rock climbing.

The 1-mile Castle Rock Loop trail offers a good spot for bouldering and roped climbs. The surrounding smaller rocks are a great playground for children. A Guide to Rocks & Climbing map can be purchased by sending $2 (check payable to Portola & CR Foundation) and a self-addressed, #10 envelope (9-1/2 x 4-1/8) stamped with 2 stamps for each map or you may purchase maps at the entrance station when staffed.

• Practice low-impact climbing and leave no trace visit. Properly dispose of all trash and protect park natural resources.


• Play by the rules. Climbing and other off-trail activities are not permitted in the San Lorenzo Headwaters natural Preserve. Check park bulletin boards before climbing for notice of possible restrictions to protect nesting birds, other wildlife and areas recovering from overuse.


• Use Natural-colored chalk. Use a chalk ball.


• Help prevent erosion. Use only existing access trails. Please carry (rather than drag) crash pads. The park's topsoil is fragile and easily displaced from the steep slopes in much of the park.


• Protect park vegetation. The plants and trees provide food and shelter for wildlife. Please avoid damaging mosses, lichens and branches.


• Respect the integrity of the rock and the climb. Please do not chip, glue, remove or otherwise alter the rock. Please allow two or three days after a heavy rain before climbing. Sandstone becomes much more fragile when damp.


• Get permits for groups. Ropes classes and similar activities (whether held by private, educational, non profit or commercial groups) require advance permits and insurance. For permit applications, call 831.335.6324.