[2] The county includes several large preserved areas and rivers and has been home to commercial timber and fishing industry.

During World War II most of Franklin County was used by the U.S. Army for amphibious and jungle training, for which the beaches and islands were ideal.

When the war ended and the military left, Lanark Village was established from the remaining officer's quarters.

[5] Franklin County includes part of Tate's Hell State Forest.

The extreme eastern tip of the county is bordered by the Ochlockonee River.

As of the 2020 United States census, there were 12,451 people, 4,691 households, and 2,926 families residing in the county.

As of the census[16] of 2000, there were 11,057 people, 4,096 households, and 2,727 families residing in the county.

28.70% of all households were made up of individuals, and 11.80% had someone living alone who was 65 years of age or older.