Alcatraz, "The Rock," was a military prison from 1859 to 1933 and a federal prison until what year? (within 2 years)

The final chapter for Alcatraz as a federal penitentiary concluded on March 21, 1963. The decision to close the infamous island prison was primarily a financial one. Its location in the middle of San Francisco Bay, which made it so secure, also made it incredibly expensive to operate. The cost per prisoner was nearly triple that of other federal prisons due to the logistics of transporting food, water, and supplies by boat. Furthermore, decades of exposure to the salty sea air had severely corroded the buildings, and the required repairs were deemed too costly.

Attorney General Robert F. Kennedy made the final call to shutter the facility, ending its 29-year run as America's most formidable prison. During its time, "The Rock" housed notorious criminals like Al Capone and George "Machine Gun" Kelly, building a reputation as an inescapable fortress. After its closure, the island was famously occupied by Native American activists from 1969 to 1971, bringing a new chapter to its history. Today, it is managed by the National Park Service as one of the country's most popular tourist destinations.