Darien (formerly Cass) is a city in DuPage County, Illinois, United States. Per the 2020 census, the population was 22,011. A southwestern suburb of Chicago, Darien was named after the town of Darien, Connecticut. Darien is just north of I-55 and Historic U.S. Route 66 (now Frontage Road). The entire south edge of the town borders Waterfall Glen.
Zip Codes in Darien, IL that we also serve: 60561