It was not the first such discovery in the park, a centerpiece of Greenwich Village that was built in the early 19th century atop a potter's field and former parade ground. Bones also were found during at least one of three previous excavations, the agency said.
The bones, that were found without any accompanying coffin, will be analyzed by a forensic archaeologist and reburied respectfully, the department said. It appeared the bones had been moved from their original burial site many times over the years as the area was transformed into an urban plaza.
Washington Square Park, bordered by landmark 19th century townhouses and New York University's campus, is a traditional gathering spot for students and Greenwich Village residents.