Back River is a tidal estuary in Baltimore County, Maryland, located about 2 miles (3 km) east of the city of Baltimore. The estuary extends from Essex, Maryland, southeast for about 8.8 miles (14.2 km) to the Chesapeake Bay. The watershed area is 39,075 acres (15,813 ha) and includes Essex Skypark Airport and the Back River Wastewater Treatment Plant. The river is shared between Essex, MD, Dundalk, MD, and Edgemere, MD