Rocky Ridge is a prominent Berkeley Hills landmark and the second-highest mountain in Contra Costa County, overlooking Lafayette, Moraga, and Orinda. Its crest is lined with unusual sedimentary rock outcrops that gave it its present name, while the ridge itself forms an important drainage divide between waters flowing toward San Francisco Bay and toward Walnut Creek and the Carquinez Strait. Built of Miocene marine sedimentary rock uplifted and folded along active faults, it preserves marine fossils high above sea level. Its cool, fog-influenced climate supports varied habitats and wildlife, and its slopes offer hiking access, protected watershed lands, and wide Bay Area views.