Castle Rock State Park is a 5,242-acre mountain park in the Santa Cruz Mountains, mostly in Santa Cruz County, known for wild forests, steep canyons, and distinctive sandstone formations including Castle Rock itself. Its natural landscape of coast redwood, Douglas fir, and madrone has made it both a scenic destination and a popular rock-climbing area. Thirty-two miles of trails connect the park to a wider regional network, and it serves as a common starting point for the Skyline-to-the-Sea Trail. Established in 1968, the park avoided planned closure in 2012 through nonprofit support and donations, and gained expanded visitor facilities with a new entrance in 2019.