https://youtu.be/2o3Y2vgurUk Alcatraz Island, San Francisco, California . Alcatraz Island is a small island 1.25 miles (2.01 km) offshore from San Francisco, California, United States. The island was developed in the mid-19th century with facilities for a lighthouse, a military fortification, and a military prison. In 1934, the island was converted into a federal prison, Alcatraz Federal Peniten..