The Diamond Historic District is a seaside, 69.5-acre (28.1 ha) National Register historic district in Lynn, Massachusetts. Established by the National Park Service in 1996, the district is situated between downtown Lynn and the Atlantic Ocean—bounded roughly by Broad and Lewis Streets to the north, Lynn Shore Drive to the southeast, Nahant Street to the west, and Eastern Avenue to the east. The Diamond Historic District encompasses 590 contributing resources.