Divers Uncovered the Remains of a Forgotten Hospital Beneath the Sea Near One of America’s Most Remote Locations

Underwater archaeologists have identified the remnants of a quarantine infirmary and a modest burial ground on a sunken island within Dry Tortugas National Park, near the historic Fort Jefferson that shaped America’s most remote 19th‑century outposts.

The massive fort, erected to safeguard Gulf‑Coast shipping lanes, housed soldiers, inmates, laborers and support crews for decades, yet the everyday lives of those who toiled there have long been eclipsed by the fort’s stone walls.

The newly uncovered sites add depth to that narrative, revealing medical facilities used during epidemic waves and the quiet resting places of individuals who have largely vanished from the record.

Rediscovered Burial Plot Linked to Fort Jefferson

According to a University of Miami press release, divers conducting a sonar survey around Garden Key — the island that supports Fort Jefferson — pinpointed the Fort Jefferson Post Cemetery, a burial site noted in historic documents.

Survey records suggest roughly twelve interments, primarily soldiers stationed at the fort and prisoners held there, with a handful of civilians also laid to rest.

One grave stood out: records identify it as the burial of John Greer, a laborer who died in 1861.

“On the day we surveyed the site, we counted 25 pylons in all,” explained former Rosenstiel School graduate student Devon Fogarty. “We were preparing to return to our boat, when I noticed a rectangular-shaped patch of seaweed.”

Fogarty’s team found Greer’s marker fashioned from a slab of greywacke — the same stone that formed Fort Jefferson’s first floor — cut into a headstone and etched with his name and death year. The precise cause of his demise remains undocumented.

Quarantine Facility Tied to 19th‑Century Yellow Fever Outbreaks

The expedition also revealed the footprint of a quarantine hospital, a structure tied to efforts to contain yellow fever epidemics that swept the region in the 1860s and 1870s.

Historical accounts describe a chain of island‑based quarantine stations surrounding Fort Jefferson, where infected individuals were isolated and treated during the disease’s most lethal phases.

Many of those early hospitals fell silent after Fort Jefferson was abandoned in 1873. A renewed medical role emerged between 1890 and 1900 when the U.S. Marine Hospital Service operated on the island, prompting the need for a fresh isolation ward.

Hidden Lives Emerge From a Shifting Landscape

Beyond the bricks and stone, the discovery is valuable for the human stories it hints at.

“This intriguing find highlights the potential for untold stories in Dry Tortugas National Park, both above and below the water,” maritime archaeologist Josh Marano, who directed the project, said in a statement. “Although much of the history of Fort Jefferson focuses on the fortification itself and some of its infamous prisoners, we are actively working to tell the stories of the enslaved people, women, children and civilian laborers.”

Researchers are now intensifying efforts to document the experiences of enslaved individuals, women, children and civilian workers who formed the fabric of Fort Jefferson’s community. The survey also underscores how dramatically the environment has changed.

Project notes indicate that the hospital and cemetery were originally constructed on solid land; over time, shifting island contours, severe storms, erosion and climate change have submerged the sites beneath the sea.