Du Page County, IL - Resident Population in DuPage County, IL was 921.21300 Thous. of Persons in January of 2023, according to the United States Federal Reserve. Historically, Du Page County, IL - Resident Population in DuPage County, IL reached a record high of 933.66900 in January of 2015 and a record low of 487.96600 in January of 1970. Trading Economics provides the current actual value, an historical data chart and related indicators for Du Page County, IL - Resident Population in DuPage County, IL - last updated from the United States Federal Reserve on May of 2024.