As of the 2010 census, its population was 1,702 and it contained 744 housing units.

[4] Washington Township was organized in 1816.

[5] According to the 2010 census, the township has a total area of 35.29 square miles (91.4 km2), of which 35.19 square miles (91.1 km2) (or 99.72%) is land and 0.09 square miles (0.23 km2) (or 0.26%) is water.

[4] The township contains several cemeteries: Adams (a.k.a.

Pisgah), Crown Hill, Fouts/Robison, Frazier Family, Glass Family, Grayfriar-McMillen, Lawrence, Izzard, New Washington Christian Church, Staples, Work (a.k.a.