Three miles to the west of Garden Key (which is where Fort Jefferson is located) is Loggerhead Key, home of the Loggerhead Lighthouse, also known as the Dry Tortugas Light. The Garden Key Light was built in 1826, and when it was projected in the 1850's that $35,000 would be needed to upgrade that lighthouse, a new one was built on Loggerhead Key instead: Twas completed in 1858.

Fort Jefferson spent some time, as has many a starfort, as a really unpleasant place in which to be incarcerated. During the Civil War, two civilian prisoners managed to paddle they way over to Loggerhead Key with the help of wooden planks. They found the lighthouse keeper's boat unguarded and sailed it to Havana, Cuba. The Cubans extradited these gentlemen back to the US, which plopped them back at Fort Jefferson. One of these escapees, John W. Adare, was undaunted and paddled his way back to Loggerhead Key, only to find that the lighthouse keeper had learned his lesson, and locked up his boat. Adare was recaptured the following day.