Dupo is a village in St. Clair County, Illinois, United States. As of the 2020 census, Dupo had a population of 3,996. The village was settled in about 1750 and was incorporated in 1907. Its modern name, adopted in the early 20th century, is shortened from Prairie du Pont ("Bridge Prairie").

History

In the Mississippian period, Dupo was the site of one of several

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