| Official Name: | Hamilton Township |
| Settlement Type: | Township |
| Subdivision Type: | Country |
| Subdivision Type1: | State |
| Subdivision Type2: | County |
| Subdivision Name2: | Decatur |
| Area Total Km2: | 65.53 |
| Area Land Km2: | 65.17 |
| Area Water Km2: | 0.35 |
| Unit Pref: | Imperial |
| Area Total Sq Mi: | 25.3 |
| Area Land Sq Mi: | 25.16 |
| Area Water Sq Mi: | 0.14 |
| Area Water Percent: | 0.53 |
| Population As Of: | 2000 |
| Population Total: | 180 |
| Population Density Km2: | 2.8 |
| Population Density Sq Mi: | 7.2 |
| Elevation M: | 302 |
| Elevation Ft: | 991 |
| Coordinates: | 40.61°N -93.7239°W |
| Blank Name: | GNIS feature ID |
| Blank Info: | 0467991 |
Hamilton Township is a township in Decatur County, Iowa, United States. As of the 2000 census, its population was 180.
Hamilton Township was created in 1850. It is named for county commissioner William Hamilton.[1]
Hamilton Township covers an area of 25.3 square miles (65.53 square kilometers); of this, 0.14 square miles (0.35 square kilometers) or 0.53 percent is water. The streams of Kilgore Creek and Marks Branch run through this township.
The township contains seven cemeteries: Campbell, Chase (historical), Cowles, Dale, Gammill, Hamilton and New Salem.