The 31st District consists of all or part of Beach Park, Gages Lake, Grandwood Park, Grayslake, Green Oaks, Gurnee, Hainesville, Libertyville, Lindenhurst, Long Lake, Old Mill Creek, Round Lake, Round Lake Beach, Round Lake Heights, Round Lake Park, Third Lake, Venetian Village, Wadsworth, Waukegan, Winthrop Harbor and Zion.