Prairie du Long Township is located in St. Clair County, Illinois. As of the 2010 census, its population was 2,244 and it contained 864 housing units.[4]
Geography
According to the 2010 census, the township has a total area of 35.97 square miles (93.2 km2), of which 35.53 square miles (92.0 km2) (or 98.78%) is land and 0.44 square miles (1.1 km2) (or 1.22%) is water.[4]