About the town » Dupo, Saint Clair County, Illinois, United States
Source: Wikipedia Information
Dupo is a village in St. Clair County, Illinois, United States. The population was 4,138 at the 2010 census, an increase from 3,933 in 2000. The village was settled in about 1750 and was incorporated in 1876. Its name is derived from Common Fields of Prairie du Pont (French: Bridge Prairie).
