Marion Township is one of twelve townships in Boone County, Indiana. As of the 2010 census, its population was 1,233 and it contained 506 housing units.
According to the 2010 census, the township has a total area of , of which (or 99.98%) is land and (or 0.02%) is water.
The township contains two cemeteries: Bethel and Parr-Jones.