The boundary lines of Sumter County are as follows: Beginning at the intersection of the township line dividing townships seventeen and eighteen south, with the range line dividing ranges twenty-three and twenty-four east; thence west on said township line to the thread of the Withlacoochee River; thence southerly up the thread of said river to the junction therewith of the Little Withlacoochee River; thence southeasterly up the thread of the said Little Withlacoochee River to the head of the same; thence east to the range line dividing ranges twenty-two and twenty-three east; thence south on said range line to the thread of the Withlacoochee River; thence easterly along the thread of the said river to its intersection by the range line dividing ranges twenty-three and twenty-four east; thence north on said range line to the place of beginning.