Fla. Stat. § 7.24

The boundary lines of Hamilton County are as follows: Beginning in the thread of the Withlacoochee River where the boundary line between the States of Georgia and Florida intersects said river; thence southerly along the thread of said river to where it joins the thread of the Suwannee River; thence east and northerly following the thread of said Suwannee River where same is intersected by the boundary line between the States of Georgia and Florida; thence west along said boundary line to the place of beginning.