Eastham (EES-tuhm), town (1990 pop. 4,462), Barnstable co., SE Mass., on N arm of Cape Cod, 19 mi/31 km ENE of Barnstable; 41°51'N 70°00'W. Summer resort; agr. Formerly shipping and fishing port. Has lighthouse and coast guard station. Settled 1644, inc. 1651. Includes North Eastham village (1990 pop. 1,570). Hq. and visitor center Cape Cod Natl. Seashore.