Washington Township is one of thirteen townships in Putnam County, Indiana. As of the 2020 census, its population was 2,488 (slightly down from 2,493 at 2010) and it contained 1,071 housing units.
The Putnam County Bridge No. 159 and Lycurgus Stoner House are listed on the National Register of Historic Places.
According to the 2010 census, the township has a total area of , of which (or 99.42%) is land and (or 0.58%) is water.
(This list is based on USGS data and may include former settlements.)