Washington Township is one of thirteen townships in Owen County, Indiana, United States. As of the 2020 census, its population was 6,387 (up from 6,164 at 2010) and it contained 2,616 housing units.
Washington Township was organized in 1819. It was named for George Washington.
The CCC Recreation Building-Nature Museum, McCormick's Creek State Park Entrance and Gatehouse, Secrest-Wampler House, and Stone Arch Bridge over McCormick's Creek are listed on the National Register of Historic Places.
According to the 2010 census, the township has a total area of , of which (or 99.64%) is land and (or 0.36%) is water. The White River defines the northeastern border of the township.
(This list is based on USGS data and may include former settlements.)
The township contains these seven cemeteries: Blair, Chambersville, Mount Moriah, River Hill, Riverside, Rose and Witham.