| Place Name | Greencastle Township |
| Place Type | Township |
| ZIP Code(s) | 50078 50106 50158 |
| County | Marshall County |
| Area Code(s) | 641 |
| Timezone | Central Daylight Time (CDT) |
| Population (2021) | 920 |
| Majority Ethnicity | White 97.02% |
| Metro/Micro Stats Area | Marshalltown, IA |
| US Congressional District(s) | Iowa 1st |
| State House Districts | 72 |
| State Senate Districts | 36 |
| Race/Ethnicy | Percentage of Population (2021) |
|---|---|
| White | 97.02% |
| African American | 0% |
| Hispanic | 0% |
| Asian | 0.43% |
| Native American | 0.21% |
| Hawaiin/Pacific Islander | 2.34% |