DuPage County (/ ˌ d uː ˈ p eɪ dʒ / doo-PAYJ) is a county in the U.S. state of Illinois, and one of the collar counties of the Chicago metropolitan area. As of the 2020 census , the population was 932,877, making it Illinois' second-most populous county .
National protected area. Great River National Wildlife Refuge (part); Climate and weather. In recent years, average temperatures in the county seat of Quincy have ranged from a low of 16 °F (−9 °C) in January to a high of 88 °F (31 °C) in July, although a record low of −21 °F (−29 °C) was recorded in January 1979 and a record high of 105 °F (41 °C) was recorded in July 2005.
DuPage Convention & Visitors Bureau 915 Harger Road, Suite 120 Oak Brook, IL 60523-1476 (630) 575-8070