| Place Name | St. Marys |
| Place Type | City |
| ZIP Code(s) | 50229 50240 50241 |
| County | Warren County |
| Area Code(s) | 641 |
| Timezone | Central Daylight Time (CDT) |
| Population (2022) | 126 |
| Population Growth Rate (2010-19) | -14.96% |
| Majority Ethnicity | White 89.29% |
| Metro/Micro Stats Area | Des Moines-West Des Moines, IA |
| US Congressional District(s) | Iowa 3rd |
| State House Districts | 25 |
| State Senate Districts | 13 |
| Race/Ethnicy | Percentage of Population (2021) |
|---|---|
| White | 89.29% |
| African American | 1.79% |
| Hispanic | 6.25% |
| Asian | 0% |
| Native American | 0.89% |
| Hawaiin/Pacific Islander | 1.79% |