Sierra Azul
 The Sierra Azul is a mountain range in Santa Clara County California. It is a part of the larger Santa Cruz Mountains. Part of the range is within the Sierra Azul Open Space Preserve.The highest peak is Mount Umunhum the site of the former Almaden Air Force Station radar site and the current location of a NEXRAD weather radar of the National Weather Service which serves the San Francisco Bay Area and Monterey Bay Area.