Monument Peak is a mountain in the East Bay of the San Francisco Bay Area, on a Diablo Range ridge shared with Mount Allison and Mission Peak. The ridge forms part of the boundary between Alameda and Santa Clara counties, and the summit lies just inside the southern edge of Mission Peak Regional Preserve in Alameda County. Trails reach it from Ed R. Levin County Park to the south and from the Bay Area Ridge Trail to the north. A major modern landmark is its broadcast antenna, built on July 1, 1988, a free-standing tower 605.2 feet high that carries television channels 14, 26, 36, and 48.