| Official Name: | Waterloo Township |
| Settlement Type: | Township |
| Subdivision Type: | Country |
| Subdivision Name: | United States |
| Subdivision Type1: | State |
| Subdivision Name1: | Indiana |
| Subdivision Type2: | County |
| Subdivision Name2: | Fayette |
| Government Type: | Indiana township |
| Area Total Sq Mi: | 17.15 |
| Area Land Sq Mi: | 17.15 |
| Area Water Sq Mi: | 0 |
| Population As Of: | 2020 |
| Population Footnotes: | [1] |
| Population Total: | 531 |
| Population Density Sq Mi: | 35.4 |
| Elevation Footnotes: | [2] |
| Elevation M: | 307 |
| Elevation Ft: | 1007 |
| Coordinates: | 39.695°N -85.0786°W |
| Blank Name: | FIPS code |
| Blank Info: | 18-81314[3] |
| Blank1 Name: | GNIS feature ID |
| Blank1 Info: | 454026 |
Waterloo Township is one of nine townships in Fayette County, Indiana. As of the 2010 census, its population was 607 and it contained 240 housing units.[4]
Waterloo Township was organized in 1821.[5]
The Thomas Ranck Round Barn was added to the National Register of Historic Places in 1983.
According to the 2010 census, the township has a total area of, all land.[4]