Physical Characteristics. Flagler County is on Florida's northeast coast and is bordered by St. Johns, Putnam, and Volusia counties. The county has 490.78 square miles of land and 16.70 square miles of water for a total of 507.48 square miles. The average January temperature is 58.6 degrees Fahrenheit, and the average August temperature is 81.6 degrees Fahrenheit. The average annual rainfall is 50.74 inches.
History. Flagler County was established in 1917 from portions of St. Johns and Volusia counties and named for Henry Morrison Flagler, developer of the Florida East Coast Railroad.
