DuPage County, Illinois, USA
County or equivalent
Location overview
DuPage County is in northeastern Illinois, in the western suburbs of Chicago. Wheaton has been its county seat since 1867, following the transfer of county offices from Naperville. The county was established in 1839 from part of Cook County and takes its name from the DuPage River. It contains nine townships, including Addison, Bloomingdale, Downers Grove, Lisle, Milton, Naperville, Wayne, Winfield and York.