Mt. Eden was an unincorporated agricultural district in Eden Township, Alameda County, California, United States. It was annexed by the City of Hayward. It lies at an elevation of 43 feet.
Mt. Eden was founded in 1850 by a group of farmers from Mount Eden, Kentucky, drawn to California by the Gold Rush. The party disbanded upon reaching the San Francisco Bay, but a few settled at a road crossing where they nailed a sign "Mt. Eden" to two trees, and the name stuck. A post office opened in 1860 and was in continuous operation until 1953.