When the county was formed in 1827, it was divided into four townships: Medina, Warren, Pike and Mound. Over the following decades, many changes were made to the township borders and eight new townships were created. Pine and Washington were the first of these, in March 1830; Steuben followed in 1834. Liberty was formed in 1843, Adams in 1848, then Jordan in 1850. Kent and Prairie were the last to be created, in 1864. , Prairie Township, at , has the lowest population density; it covers more area than any of the other townships—nearly —and contains no incorporated towns. The highest density is in Washington Township, which has ; it includes Williamsport, the county's largest town, and covers only about .