Fayetteville Township is located in St. Clair County, Illinois. As of the 2010 census, its population was 1,668 and it contained 722 housing units.
Geography
According to the 2010 census, the township has a total area of 43.85 square miles (113.6 km2), of which 42.96 square miles (111.3 km2) (or 97.97%) is land and 0.89 square miles (2.3 km2) (or 2.03%) is water.