Castle Rock shares borders with two major parks Diablo Foothills Regional Park and Shell Ridge Open Space. Diablo Foothills Regional Park connects to Mount Diablo State Park which can also be accessed by car at the parks north gate. The gate is about a 3 mile drive from the castle rock parking area but is actually only about 1 mile away.
Down the road from the Castle Rock parking lot are a few sets of stables where you can take horse riding lessons or book a ride down the park trails. Further down the road is Northgate High School and beyond that are the cities of Walnut Creek and Concord.