California Historical Landmarks in Contra Costa County
California Historical Landmark 905
Mount Diablo State Park
Mount Diablo had been a home with spiritual significance to the Costanoan Indians for at least 500 years when Spanish explorers viewed the mountain in 1772. In 1851 Mount Diablo was selected as the initial point for land surveys of Northern California and Nevada, with the Mount Diablo Base and Meridian Lines originating at its peak. Due to the mountain's variations in wind, rainfall, and temperature, it is also a preserve for a wide variety of plant and animal life.
Citation from California Office of Historic Preservation