Complex sentence: In addition, The Trustees of Reservations manage the U.S. Army Corps of Engineers Tully Lake Campground in Royalston and Norton Point Beach in Edgartown, which is owned by the county government of Dukes County.
Split into simpler sentences: In addition, The Trustees of Reservations manage the U.S. Army Corps of Engineers Tully Lake Campground in Royalston. They also manage the Norton Point Beach in Edgartown, which is owned by the county government of Dukes County.