Washington Township is one of fourteen townships in Carroll County, Indiana. As of the 2020 census, its population was 551 (slightly up from 549 at 2010) and it contained 297 housing units.
Washington Township was organized in 1835.
According to the 2010 census, the township has a total area of , of which (or 99.97%) is land and (or 0.03%) is water.
The township contains two cemeteries: Hopewell and Rock Creek.