"This MROSD preserve is a 3117-acre treasure of redwood forests, clear-flowing streams, steep-sided canyons and long ridges. Its size and its rugged terrain make it a place to find both quiet seclusion and long trails for strenuous hiking trips. This northernmost redwood forest in San Mateo County is just minutes from the urban San Francisco Peninsula. The preserve extends westward for 3 miles from the 2000-foot-high crest of the Santa Cruz Mountains. East across Skyline Boulevard are the San Francisco Watershed lands, Huddart Park, and the Phleger Estate. From the Skyline crest, three ridges divide the preserve into two main canyons trending west. Between Harkins and Tunitas ridges flows Purisima Creek, the centerpiece of the preserve. This trail guide includes the following trails: Purisma Creek Trail, A Loop Trip from the North Ridge, Grabtown Gulch Loop, Bald Knob, and Irish Ridge Exploration, The Bay Area Ridge Trail."