Franklin County is a county along the Gulf of Mexico in the panhandle of the U.S. state of Florida. As of the 2020 census, the population was 12,451, making it the third-least populous county in Florida. The county seat is Apalachicola. The county includes several large preserved areas and rivers and has been home to commercial timber and fishing indu…Franklin County is a county along the Gulf of Mexico in the panhandle of the U.S. state of Florida. As of the 2020 census, the population was 12,451, making it the third-least populous county in Florida. The county seat is Apalachicola. The county includes several large preserved areas and rivers and has been home to commercial timber and fishing industry. More recently it has become popular for tourism and retirement. It includes several rivers, state parks, and islands.