On December 3, 1818, Illinois was admitted to the Union as the 21st state. Its admission followed rapid population growth in the Old Northwest, where settlers took advantage of fertile prairies and river routes. Statehood shifted political power westward and added new voices to congressional debates over issues such as slavery and internal improvements. Illinois became formally a “free state,” although racial discrimination remained widespread. In time, Illinois produced national figures, including Abraham Lincoln. The state’s entry into the Union helped solidify U.S. control over the Mississippi and Ohio River regions.
