Fla. Stat. § 7.19
The boundary lines of Franklin County are as follows: Beginning at a point on the Apalachicola River, known as the mouth of Black or Owl Creek; thence northerly up the western bank of said creek to where the same intersects the middle section line of section twenty-six, township five south, range eight west; thence due east on the middle section line to the thread of the Ochlockonee River; thence south and easterly following the thread of said river, and the thread of such channel thereof as may be necessary to include the islands in said river; to a point directly south of the southernmost point of Grass Island; thence along a straight line to the center point of the U.S. 98 (State Road 30) bridge across Ochlockonee Bay; thence east-southeast to a point directly north of the easternmost point of James Island; thence easterly to the boundary line of the State of Florida; thence south and westerly along said boundary line, including the waters of the Gulf of Mexico within the jurisdiction of the State of Florida, to the Forbes line, produced southerly; thence following the Forbes line to the Jackson River; thence follow the Jackson River until it joins the Apalachicola River; thence northerly along the Apalachicola River to the mouth of the Brothers River; thence follow the Brothers River until it intersects the stream known as Brickyard Cutoff; thence follow Brickyard Cutoff to the Apalachicola River; thence northerly along the thread of said river to the place of beginning.
Fla. Stat. § 7.19