Caseyville Township is located in St. Clair County, Illinois, United States. As of the 2010 census, its population was 31,996 and it contained 14,054 housing units.[2]
Geography
According to the 2010 census, the township has a total area of 35.11 square miles (90.9 km2), of which 34.87 square miles (90.3 km2) (or 99.32%) is land and 0.23 square miles (0.60 km2) (or 0.66%) is water.[2]