Gulf County is a county located in the U.S. state of Florida. Its county seat is Port St. Joe, Florida. Gulf County was created in 1925 and was named for the Gulf of Mexico. Its county seat, Port Saint Joe was the site of Florida's first Constitutional Convention in 1838. Gulf County has a total area of approximately 745 square miles of which 74% is land and 26% water. As of the 2000 census, there were13,332 people, 4,931 households, and 3,535 families residing in Gulf County, FL.