| Official Name: | Washington Township, Buchanan County |
| Settlement Type: | Township |
| Subdivision Type: | Country |
| Subdivision Type1: | State |
| Subdivision Type2: | County |
| Subdivision Name2: | Buchanan |
| Area Total Km2: | 94.28 |
| Area Land Km2: | 92.34 |
| Area Water Km2: | 1.94 |
| Unit Pref: | Imperial |
| Area Total Sq Mi: | 36.4 |
| Area Land Sq Mi: | 35.65 |
| Area Water Sq Mi: | 0.75 |
| Population As Of: | 2000 |
| Population Total: | 4540 |
| Population Density Km2: | 49.2 |
| Population Density Sq Mi: | 127.3 |
| Elevation Footnotes: | [1] |
| Elevation M: | 292 |
| Elevation Ft: | 958 |
| Coordinates: | 42.5139°N -91.9092°W |
| Blank Name: | FIPS code |
| Blank Info: | 19-94458[2] |
| Blank1 Name: | GNIS feature ID |
| Blank1 Info: | 0468904 |
Washington Township is one of sixteen townships in Buchanan County, Iowa, United States. As of the 2000 census, its population was 4,540.
Washington Township covers an area of 36.4sqmi and contains one incorporated settlement, Independence (the county seat). The unincorporated community of Otterville also lies in the township. According to the USGS, it contains three cemeteries: German Catholic, Otterville and Saint Johns.