Cobb Island, Northampton co., E Va., barrier isl. off Atlantic Ocean shore, 13 mi/21 km ENE of Cape Charles city; 5 mi/8 km long. Coast Guard station, lighthouse. Cobb Isl. Bay to W. Great Machipongo Inlet and Hog Isl. to N, Sand Shoal Inlet and Wreck Isl. to S.