What is the name of the Island located in San Francisco Bay, 1.25 miles offshore, with facilities for a lighthouse, a military prison, and the Parade Grounds, a large concrete open area?
Parade Grounds: The Parade Grounds is a large concrete open area on the south end of Alcatraz Island, off the coast of San Francisco, USA. Alcatraz Island: Alcatraz Island ( ) is located in San Francisco Bay, 1.25 mi offshore from San Francisco, California, United States. Alcatraz Island:  The small island was developed with facilities for a lighthouse, a military fortification, a military prison (1868), and a federal prison from 1934 until 1963.
Alcatraz Island