Flagler Beach is a city in Flagler County in the U.S. state of Florida. The population was 5,160 at the 2020 census. Flagler Beach is part of the Deltona–Daytona Beach–Ormond Beach, FL metropolitan statistical area. It is named for oil tycoon and Florida railroad developer Henry Flagler, who was a key figure in the development of East Florida as resort and vacation destinations.