Illinois Route 121 is a state highway located in central Illinois. It runs approximately 40 miles, connecting the towns of Decatur and Macon. The route primarily serves local traffic and provides access to various communities along its path. The highway is known for its rural scenery and is an important connector for residents in the area. It intersects with several other roads, facilitating travel to nearby cities and attractions. Overall, Illinois Route 121 plays a vital role in the transportation network of central Illinois.