Amelia Island (uh-MEEL-yuh), Nassau co., extreme NE Fla., one of the Sea Isls. in Atlantic Ocean, separated from the mainland by salt marshes (bridged by road and RR); extends 13.5 mi/21.7 km S from mouth of St. Marys R. and is c.2 mi/3.2 km wide; 30°40'N 81°27'W. Fernandina Beach resort, Fort Clinch State Park, and a lighthouse are located in the N part of isl.
