Almost 70 miles (113 km) west of Key West lies the remote Dry Tortugas National Park. This 100-square mile park is mostly open water with seven small islands. Accessible only by boat or seaplane, the park is known the world over as the home of magnificent Fort Jefferson, picturesque blue waters, superlative coral reefs and marine life, and the vast assortment of bird life that frequents the area.
Historical records indicate that this grave marker with the name “John Greer, Nov 5, 1861”, was a civilian laborer, who was presumably buried on the now-submerged island near the Fort Jefferson in the area currently known as Bird Key. The island once housed a quarantine hospital and a cemetery that probably still contains the remains of dozens of American service members.
https://www.nps.gov/drto/index.htm
