Nearly 60 years ago, Sylvia Murphy was clearing brush from around her rented cottage when she tripped over an iron bar, stumbling upon an abandoned burial site hidden beneath a tamarind tree in the Upper Keys town of Tavernier.

“I was lying on my belly — looking nose to nose at three gravestones,” recalls Murphy, now a Monroe County commissioner. “One was straight up. One was tipped. And one was flat on the ground.”

Murphy, then 18, became the volunteer caretaker of the tiny, abandoned cemetery, whose boundaries were marked by the iron bars. She lovingly kept it up, adorning the graves with flowers, though she didn’t know a soul buried there.

After she moved in 1955, the burial ground was once again abandoned and mostly forgotten — until a Brazilian couple purchased the property and applied for a permit to build a waterfront home last year.

The Monroe County Historical Preservation Commission got involved, and last fall, the Ballast Trail Cemetery became one of five Keys burial places listed on the Florida Division of Historical Resources’ Master Site File.

The designation didn’t prevent the new owners from building, but it does hold them accountable for the cemetery.

“It’s a felony to mess with it,” said Diane Silvia, executive director of the Historic Florida Keys Foundation and a preservation planner for the county. “So listing it certainly should save it.”

The Tavernier site is safe, but Sarah Miller, a region director of the Florida Public Archeology Network, says numerous final resting sites are not listed.

“Historic cemeteries are disappearing from our landscape — it’s a national and statewide problem,” Miller said. “They are very fragile historic resources that we need to preserve. They are our outdoor museums.”

That’s why she developed the Cemetery Resources Protection Training — CRPT, or “crypt,” for short. The $15 course teaches citizens and local governments how to save cemeteries, memorial sites, unmarked burials and single gravesites.

Miller told the 15 or so people gathered for a recent session in Key West that the most important step is to add the place to the state’s Master Site File, which so far lists 1,103 historic cemeteries and burial sites. The website findagrave.com, meanwhile, includes 4,429 Florida locations (including some duplications.)

“We don’t know how many there are, but we know there are a lot more that we don’t have,” said Vincent “Chip” Birdsong, supervisor of the Master Site File.

The list is especially sparse in South Florida, with just 20 sites in Miami-Dade, Broward and Monroe combined.

“Where there’s lots of people, there’s lots of dead people,” Miller said.

The key requirement for listing, she said, is that the site be at least 50 years old.

“It doesn’t have to be like the National Register where so-and-so was buried there,” Miller said. “It doesn’t have to have a Revolutionary War hero or anything grand.”

Miami-Dade has nine cemeteries listed on the site. Kathleen Slesnick Kauffman, the county’s chief historic preservation chief, said in an email that the county ordinance for designation of historic cemeteries requires special significance such as an association with a historic event like the Civil War, pioneers buried there or “amazing architectural or design features.”