Workers uncovered a young Irishman's grave in New York's Greenwich Village more than 200 years after he died.

Now authorities are determined to solve the mystery of the life and death of the Co Kildare man.

New York City Dept of Parks and Recreation workers expected to find unidentified bones when they dug below the city's Washington Square Park -- more than 20,000 people are believed to be buried in the former graveyard. But they discovered the 210-year-old 3ft-high sandstone gravestone of a Co Kildare man who died in 1799.

Its writing, still clear, read: "Here lies the body of James Jackson, who departed this life the 22nd day of September, 1799 aged 28 years, native of the county of Kildare, Ireland."

Workers have several times found skeletons during the restoration of the park, but Jackson's stone was the first burial marker.

"It's very unusual," John H Geismar, the archaeological consultant who made the discovery, said. "In fact, I'm stunned."

The New York Historical society has identified one James Jackson of 19 East George Street, who was listed in the city death records on September 23, 1799, Ms Geismar said. His occupation is listed as a watchman, though a city directory at the time listed him as a grocer.

Diana de Zerega Wall, an archaeology professor at the City University of New York, said that at the time Jackson was buried, the city was wrestling with a series of yellow fever outbreaks and he may have died from the illness.

Victims were buried there away from the then centre of town, as a safety measure.

After the discovery, workers dug seven feet below the gravestone but found no body. It is thought it may have been moved when the area was developed into parade grounds.

Parks Commissioner Adrian Benepe said that even in the absence of a body, the city hopes to learn more about the young Irish immigrant.