Fernandina Beach is a city in Nassau County, Florida, United States, on Amelia Island. It is the northernmost city on Florida's Atlantic coast, and is one of the principal municipalities comprising Greater Jacksonville. The area was first inhabited by the Timucuan Indian tribe. Located on Amelia Island, known as the "Isle of 8 Flags", Fernandina has had the flags of the following nations flown over it since 1562: France, Spain, Great Britain, Spain (again), the Republic of Florida, the Green Cross of Florida, Mexico, the Confederate States of America, and the United States. It is the only municipality in the United States that has flown eight different national flags.
According to the 2010 census, the city population was 11,487. It is the seat of Nassau County.