First built in the mid-17th century, this earthwork fort has stood watch over Marblehead harbor for more than three centuries, defending it first from pirates and the French during colonial times, and later from various enemies during subsequent wars. It last operated as a fort during the Civil War, and was turned over to the town in the 1920s.

Today, the well-preserved fort is ringed with benches overlooking Marblehead harbor and is home to at least a half-dozen plaques explaining various aspects of its historical significance. A grassy area at the center of the fort is just big enough for a game of catch or frisbee.

There is no vehicle access to Fort Sewall, but a small parking lot is available at Front Street and Fort Beach Lane, adjacent to Fort Beach. The fort is a short walk up the hill.