Washington Township is one of eleven townships in Clay County, Indiana. As of the 2020 census, its population was 750 (down from 780 at 2010) and it contained 346 housing units.
Indiana State Highway Bridge 46-11-1316 was listed on the National Register of Historic Places in 2000.
According to the 2010 census, the township has a total area of , all land.
(This list is based on USGS data and may include former settlements.)
The township contains six cemeteries: Fairview, Funk, Killion, Sixmile, Snoddy and Zenor.