The boundaries of Lyons Township are East: Harlem Avenue, West: the Cook-DuPage County (County Line Road), south: the line of 87th Street, except west of Willow Springs, where it follows the Des Plaines river to the Cook-DuPage County Line, North: the line of 39th Street (Southview Avenue, Brewster Avenue). There are seventeen municipalities in or partially within Lyons Township's thirty-seven square miles of territory: