Rikers Island is New York City’s largest jail facility.  It houses over 15,000 inmates at one time.  It is not used as a long-term hold facility for offenders, but rather it is used to house offenders awaiting trial and those serving sentences of one year or less.  It is located in the East River between Queens and Brooklyn.  The island which the facility sits on is also called Rikers Island is over 413 acres.

Alcatraz Island (slang: The Rock) is a small island located in the middle of San Francisco Bay in California, United States that served as a lighthouse, then a military fortification, and then a federal prison for the area until 1963, when it became a national recreation area.

Today, the island is a historic site supervised by the National Park Service as part of the Golden Gate National Recreation Area and is open to tours. Visitors can reach the island by ferry ride from Fisherman’s Wharf in San Francisco. It is listed as a National Historic Landmark.