The sign is small, so pay attention. There is a parking area right after the turn on Aptos Creek Road. Bicyclists tend to park at the free lot. There are trails connecting Portola to Castle Rock, Sanborn Canyon, and Big Basin. Portola is often empty - you can get the whole canyon to yourself on weekdays.
Main campground has restrooms, hot showers, and mosquitoes - each campsite has a table and stove.
Activities Hiking, Camping, Backpacking. Dogs not allowed on trails. From Highway 35, take Alpine Road southward to Portola Park Road. Travel to end of Portola Park Road. USGS Maps Henry Cowell State Park Overview Henry Cowell State Park is a lot like Big Basin , but without the rustic camping sites.