Cull Canyon Regional Recreation Area

Cull Canyon's swim lagoon has an unusual design: when it was built, a secondary dam created an inner swimming area with a sandy beach whose water level stayed independent of the reservoir's summer draw-downs, and the lagoon won a 1966 Governor's Design Award for landscape. The reservoir south of the swim area no longer exists. The swim complex is scheduled to reopen for the 2027 season; on busy weekends and holidays it reaches capacity early, after which no new swimmers are admitted. Alcohol, glass containers, and portable barbecues are not allowed in the lagoon area.

Reservable picnic areas sit outside the swim complex, and any group of 30 or more needs a reservation on any day. The park is also a stop on the developing Chabot-to-Garin Regional Trail, which follows Cull Canyon Road and Cull Creek and then continues about six miles north across East Bay Municipal Utility District land, where an EBMUD hiking permit is required, toward Anthony Chabot Regional Park.

The entrance is on Cull Canyon Road in Castro Valley, a short drive north of I-580 from the Grove Way exit (eastbound) or the Castro Valley exit and Crow Canyon Road (westbound).