Rowley is a town in Essex County, Massachusetts, United States. Part of the town comprises the census-designated place of Rowley. According to the United States Census Bureau, the town has a total area of 20.6 square miles (53.3 km²), of which, 18.7 square miles (48.5 km²) of it is land and 1.9 square miles (4.8 km²) of it (9.08%) is water. Rowley lies along the Atlantic Ocean north of Cape Ann, the mainland separated from the ocean by a small portion of Plum Island and Plum Island Sound. The island and a portion of the marshes south of Mud Creek (part of the town's northern border) are protected as part of the Parker River National Wildlife Refuge. The town has other portions which are protected, including parts of the Mill Creek Wildlife Management Area, the Georgetown-Rowley State Forest, the Willowdale State Forest, the Arthur Ewell Reservation, and the Bay Circuit Trail. Much of the eastern mainland part of town is marshy, feeding Mud Creek, Mill River and the Rowley River, which constitutes part of the town's southern border.