The National Park Service says a previously unknown slave burial ground has been discovered at the Kingsley Plantation on Fort George Island near Jacksonville, Fla.

The plantation, dating to the early 19th century, was owned by Zephaniah Kinglsey, who was a slave trader and shipper who married one of his slaves, Anna Jai. After the Civil War, the plantation came under control of the Freedmen’s Bureau, which used it to house freed slaves and provide them with farmland.

“This discovery is nothing short of momentous,” said Barbra Goodman, superintendent of the Timucan Ecological and Historic Preserve, which includes the plantation. “The fact that we can now definitely say that we have found this remarkable heritage site is very significant.”

She said the cemetery is another piece of the story that the park service strives to tell about the plantation and the people, both free and slave, who lived there.

On Saturday, the public is invited to visit the cemetery and tour the grounds. Park rangers and the park archaeologist will be on hand to answer questions.

The actual boundaries of the burial ground, the number of remains interred there and the time period that the site was an active cemetery have not been established.