Of the ports, San Francisco Bay was the most important; coastal fortifications at Fort Point was built at the edge of the Presidio, and another supporting installation at Fort Baker on the Marin Headlands. One Civil War-era fort, Post of Alcatraz Island or Fort Alcatraz, on a rocky island just inside the Golden Gate, later became an infamous Federal penitentiary, Alcatraz. The San Francisco Bay was also protected by the Navy at Mare Island, the Benicia Arsenal, and Fort Mason with the posts at San Francisco's Point San Jose, and Camp Reynolds on Angel Island. San Pedro was protected from January 1862 by "Camp Drum", later the Drum Barracks, and later a post was established at Two Harbors on Catalina Island. San Diego was only defended by a small garrison at the New San Diego Depot occupied in 1860.