The Town Of Monticello Marker, Monticello, Fl. This marker is located on US 19 on the grounds of the Post Office, in Jefferson County, Florida. It reads as : Jefferson County became Territorial Florida´s 13th county in January, 1827. In December of that year, the town of Monticello, named in honor of Thomas Jefferson´s famous Virginia home, was laid out and lots began to be sold. During the 1830s and 1840s, Monticello developed into the social, governmental, and economic center of Jefferson County. Post- Civil War fires destroyed most of the early commercial buildings, but a number of dwellings erected during those years survive. After the Civil War, economic adversity delayed further construction in Monticello until the 1880s. Most downt...