This is a 19th century military cemetery wherein the United States Army soldiers and their families were interred. Although many remains were removed for re-interment at Fort Barrancas in Pensacola, Florida, unmarked remains are still within the hallowed site.
Though it’s now fenced off and clearly marked as a burial site, it wasn’t always like that. Since I lived in the 1st house across the street, I can vouch that for many years it was simply used as a vacant field where local children played (including myself) 😦 before being clearly marked and closed off by the city of Key West. My family’s former home is the yellow one across the street!
You can find this long forgotten Army Cemetery with NO headstones but does have a single lone stone maker in the middle of the field at the corner of Angela Street & White Street here in Key West. The photo above clearly shows the stone marker and fence placard in one frame so that you can find this on your own.