The East Bay Hills form the first mountain range east of San Francisco Bay and stretch across Contra Costa and Alameda counties as part of northern California’s Coast Ranges. Though widely known by this name, the area is classified within the broader Diablo Range. The hills include sections such as the Briones, Berkeley, and San Leandro Hills, and their geologic position between the Hayward and Calaveras faults makes them especially vulnerable to earthquakes and landslides. They preserve important habitat and protected land, including rare inland coast redwoods, but are also closely tied to severe wildfire danger, intensified by changing vegetation and highlighted by the devastating 1991 Oakland firestorm.