Illinois Route 120 (IL 120) is a major east–west state highway in northeastern Illinois. It runs from U.S. Route 14 near Woodstock to Illinois Route 131 in Waukegan. It travels a distance of 34.48 miles (55.49 km) and is one of the few roads that provides direct access from McHenry County to Interstate 94 (Tri-State Tollway) in Lake County. Throughout its length, it shifts between two and four lanes as it passes through a setting that consists of open rural areas, as well as larger developments and heavy congestion.