Nassau

Municipalities in Nassau County: Fernandina Beach, Amelia Island, Yulee Bryceville, Hilliard, Callahan Land Area is Approximately 650 Square Miles Nassau County Was named for the German Duchy of Nassau and formed on December 19th, 1824. Population Estimates ( 1990 ) Nassau County - 49,127 Amelia Island - 20,000 est. Callahan - 950 (est.) Fernandina Beach - 10,000 est. Hilliard - 2,500 (est.) Yulee - 18,500 (est.)