In the late 1850 the US Army used Alcatraz to house military prisoners. They used the island from 1850-1933 before the island was transferred to the U.S. Department of Justice for use by the Federal Bureau of Prison. The prison only hold 260-275 inmates but, the prison poupulation never reached the capacity of 336 inmates.Alcatraz only house less than  1% of the total federal prison population. Many prisoners considered the living conditions at Alcatraz to be better than other Federal prisons. Serveral inmates requested to be transfered to their. From 1934-1963 the Federal prison reported 36 men (including two who tried to escape twice) were involved in 14 separate escape attempts. Twenty-three were caught, six were shot and killed during their escape, and two drowned.The escape of Frank Morris and brothers John and Clarence Anglin remain a mistery.Did they drown and die, or did they make the greatest escape from Alcatraz and  live?

Alcatraz Prison in 1934

Sources:
"Alcatraz Escape Attemps."Alcatrazhistory.com.N.D.Web.23 October.2012.http://www.alcatrazhistory.com/escapes1.htm

"A Brief of Alcatraz."Federal Bureau of Prisons.N.D.Web.23 October.2012.http://www.bop.gov/about/history/alcatraz.jsp