The United States Penitentiary is a supermax classified prison located in Marion, Illinois. The prison was built to replace Alcatraz which closed in 1963. Supermax is the name used to describe control-unit prisons or units within prisons, representing the most secure and austere levels of custody in the prison systems of the United States and other countries. ... Marion is a city in Williamson County, Illinois, United States. ... Alcatraz Island is located in the middle of San Francisco Bay in California. ... 1963 (MCMLXIII) was a common year starting on Tuesday (the link is to a full 1963 calendar). ...