As of the 2020 census, its population was 803 (down from 873 at 2010[4]) and it contained 364 housing units.

[2] County Commissioners named the township after George Washington in 1833, and it was part of Jay County.

In 1838, Washington Township became part of the newly organized Blackford County.

[5] According to the 2010 census, the township has a total area of 36.23 square miles (93.8 km2), of which 36.22 square miles (93.8 km2) (or 99.97%) is land and 0.01 square miles (0.026 km2) (or 0.03%) is water.

[4] The township contains at least nine cemeteries: Balsley, Center, Hadden, Herbaugh, Leffler, Mills, Roll, Shields, and Schmidt.