| Official Name: | Charter Oak Township |
| Settlement Type: | Township |
| Subdivision Type: | Country |
| Subdivision Type1: | State |
| Subdivision Type2: | County |
| Subdivision Name2: | Crawford |
| Area Total Km2: | 92.5 |
| Area Land Km2: | 92.46 |
| Area Water Km2: | 0.04 |
| Unit Pref: | Imperial |
| Area Total Sq Mi: | 35.71 |
| Area Land Sq Mi: | 35.7 |
| Area Water Sq Mi: | 0.02 |
| Area Water Percent: | 0.04 |
| Population As Of: | 2000 |
| Population Total: | 757 |
| Population Density Km2: | 8.2 |
| Population Density Sq Mi: | 21.2 |
| Elevation M: | 402 |
| Elevation Ft: | 1319 |
| Coordinates: | 42.0858°N -95.615°W |
| Blank Name: | GNIS feature ID |
| Blank Info: | 0467594 |
Charter Oak Township is a township in Crawford County, Iowa, United States. As of the 2010 census, its population was 704.
Charter Oak Township covers an area of 35.71sqmi and contains one incorporated settlement, Charter Oak. According to the USGS, it contains four cemeteries: Charter Oak, Saint Boniface, Saint John and Saint Paul.
The stream of Emigrant Creek runs through this township.