Fernandina Beach, FL has a population of 12,156 and is the 3,381st largest city in the United States. The population density is 1,082 per sq mi which is 269% higher than the Florida average and 1095% higher than the national average. The median age in Fernandina Beach is 53 which is approximately 28% higher than the Florida average of 42. In Fernandina Beach, 62% of the population over 15 years of age are married, 95% speak English and 2% speak Spanish. 31% of Fernandina Beach residents were born in Florida, 63% were born out of state, 0% were born outside of the United States and 5% were foreign born.