San Francisco, CA 94123
The military fort at Alcatraz took on a new role in the Civil War. Being the only completed fort in San Francisco Bay, Alcatraz was responsible for defending the city. Early in the war, ten thousand rifles were moved to Alcatraz so that they would not fall into the hands of Confederate sympathizers. In addition to this role as defender of the San Francisco Bay, Alcatraz became the official U.S. Army prison for the western states and territories in 1861.