About 360,000 visitors a year come to Plimoth Plantation, the Smithsonian-affiliated museum featuring historical reenactments of life in the colony settled by Mayflower pilgrims in 1620. But nobody knows exactly where the Plymouth colony was located. Now, Smithsonian magazine’s online site reports, researchers from the University of Massachusetts at Boston have begun an excavation to pinpoint the site.

Historians believe the colony was located about 31 / 2 miles from Plimoth Plantation (the museum uses the spelling of William Bradford, who became governor of the colony in 1621 and wrote a history of the settlement), and they know it was described by a visitor in 1623 as being on a “high hill close unto the seaside.” Today that hill is home to a graveyard, and archaeologists will use ground-penetrating radar to survey the earth before digging, to make sure they don’t disturb any graves.

So far, results have been modest, the Boston Globe reported last month — bits of pottery and porcelain, some rusted nails and bricks. The dig is part of a multi-year excavation and survey plan leading up to the 400th anniversary of the pilgrims’ landing.