Illinois Route 22, also known as Half Day Road for part of its length, is an east–west state highway in northeastern Illinois. It runs from U.S. Route 14 (Northwest Highway) in Fox River Grove to U.S. Route 41 (Skokie Highway) in Highland Park. It travels a distance of and is one of the few roads that runs almost entirely across southern Lake County while also providing access to southeastern McHenry County. Throughout its length, it shifts between two and four lanes as it passes through a frequently changing setting of scenic forestry and smaller populations, as well as busy intersections and larger developments.