Physical Characteristics. Gulf County is in northwest Florida on the Gulf coast and is bordered by Bay, Calhoun, Liberty, and Franklin counties. The county has 558.63 square miles of land and 13.30 square miles of water for a total of 571.93 square miles. The average January temperature is 53.7 degrees Fahrenheit, and the average August temperature is 81.7 degrees Fahrenheit. The average annual rainfall is 58.36 inches.
History. Gulf County was established in 1925 from a portion of Calhoun County and named for the Gulf of Mexico. Port St. Joe was one of the first towns established on the Gulf and was the terminus of the Port St. Joe Railroad, one of the first three railroads built in the U.S. In 1838 the first state constitutional convention was held in St. Joseph near present-day Port St. Joe.