List of Missouri highways

State highways in Missouri were first designated in 1922 and Missouri's system was used (along with Wisconsin's) as a plan for the entire U.S. Highway System which was created in 1926.[citation needed] In Missouri, odd-numbered highways run north-south and even-numbered highways run east-west (with a few exceptions, such as Route 112). Missouri also maintains a secondary set of roads, Missouri supplemental routes which are "lettered" rather than numbered.