Marissa Township is located in St. Clair County, Illinois. As of the 2010 census, its population was 2,468 and it contained 1,175 housing units.[2]
Geography
According to the 2010 census, the township has a total area of 35.97 square miles (93.2 km2), of which 34.44 square miles (89.2 km2) (or 95.75%) is land and 1.53 square miles (4.0 km2) (or 4.25%) is water.[2]