Addison Township, Shelby County, IndianaAddison Township is one of fourteen townships in Shelby County, Indiana. As of the 2010 census, its population was 20,585 and it contained 9,237 housing units.Addison Township was organized in 1823.GeographyAccording to the 2010 census, the township has a total area of, of which is land and is water.Cities and towns ShelbyvilleUnincorporated towns Beech Brook Knighthood Grove Rolling Ridge Walkerville