The West Martello Tower has a long history, starting in 1822 when the original survey was done by the Navy for a fort site. By 1836 the Navy’s one fort idea was replaced by the Army, who had taken over control of Key West, with a one fort (Ft. Zachary Taylor) and two advanced batteries (East & West Martello Towers) plan.
During the Civil War, Key West was occupied by the North, even though most of its citizens were Confederate sympathizers. It was the home port of the Eastern Gulf Blockading Fleet, which captured 45 Confederate blockade runners.
In 1873, work on the two towers halted. The West Martello Tower became a quarry for the locals and a target for the Ft. Taylor gunners.
During the Spanish-American War, it was used for signaling and lookout.
World Wars I & II found the tower being used for radio stations, with an anti-aircraft battery on the beach.
The Army disposed of all of its property in Key West in 1947. The two towers (hmmm….that sounds familiar…) ended up belonging to Monroe County.