Jefferson County Sesquicentennial Marker, Monticello, Fl. This marker is located on the courthouse lawn, in Monticello, Jefferson County, Florida. The marker reads as : When Florida\u27s Territorial Legislative Council established Jefferson County in January, 1827, settlers from the seaboard states already had begun to develop cotton plantations in this area. In December, 1827, the county seat received the name Monticello in honor of Thomas Jefferson\u27s famous Virginia home. Jefferson County provided many of territorial Florida\u27s most prominent leaders, including representatives to Congress and the Legislative Council, territorial judges, and the state\u27s first elected governor, William D. Moseley. Jefferson County citizens were in...