Glenn Martin National Wildlife Refuge includes the northern half of Smith Island (in Somerset County, Maryland), which lies 11 miles (18 km) west of Crisfield, Maryland, and Watts Island, (in Accomack County, Virginia), which is located between the eastern shore of Virginia and Tangier Island. Both islands are situated in the lower Chesapeake Bay. The Refuge was established in 1954 when the late Glenn L. Martin donated 2,569 acres (10.40 km²) to the U.S. Fish and Wildlife Service. Since then, donation and purchase has increased the size of the Refuge to 4,548 acres (18.41 km²). The tidal marsh, coves and creeks, and vegetated ridges of the Refuge form an important stopover and wintering area for thousands of migratory waterfowl and nesting habitat for various wildlife species. Martin National Wildlife Refuge is the largest unit of the Chesapeake Islands Refuges, which also includes Spring Island, Barren Island, and Bishops Head in Dorchester County, Maryland. The management of the Chesapeake Islands Refuges falls under the umbrella of the Chesapeake Marshlands National Wildlife Refuge Complex.