The Dry Tortugas islands, located 70 miles west of Key West, were discovered by Ponce de Leon in 1513. 
These islands, originally named Las Tortugas (Spanish for turtles - which are common to the area), was renamed Dry Tortugas by sailors who found no fresh water there. 
In the 19th century, the US constructed a lighthouse on Bush Key and a massive brick fort - known as Fort Jefferson, on Garden Key. The fort housed prisoners from the Civil war - mainly deserters and criminals. 
In 1865, four individuals convicted as conspirators in the assissination of Abraham Lincoln were jailed here. 
In October 1992, the Dry Tortugas and Fort Jefferson were designated as a US National Park.