Nassau County, Florida
Nassau County is located in the U.S. state of Florida. It is the northeasternmost county in the state. The county seat is Fernandina Beach. The population was 90,352 at the 2020 census.
Nassau County is a constituent of the Jacksonville, Florida Metropolitan Statistical Area, which accommodates around 1.68 million inhabitants as of 2022. The county is situated in Northeast Florida with a land area of 726 square miles (1,880 km2). Population growth in the county has increased by over 28,000 residents since the year 2000 as a result of Nassau's proximity to downtown Jacksonville, new housing developments, agricultural production, tourism locations, and a diversifying tax base with new industrial and commercial companies moving to the county. Nassau County is also a favored residential destination for military personnel stationed at bases in the adjacent Duval County, Florida (Naval Air Station Jacksonville, Naval Station Mayport) and Camden County, Georgia (Naval Submarine Base Kings Bay). Nassau County celebrated 200 years with its bicentennial celebration in 2024.