Demographics & People — St. Marys, Iowa
Population Overview
| Population (Census) | 112 |
| Estimated 2026 | ~100 |
| Median Age | 55.5 |
| Total Households | 52 |
| Family Households | 32 |
| Average Household Size | 2.15 |
| Diversity Index | 0.0 (relatively homogeneous) |
Race & Ethnicity
| White | 112 |
| Black or African American | 0 |
| Asian | 0 |
| Hispanic or Latino | 0 |
Heritage & Ancestry
| Group | Count |
| German | 42 |
| Unclassified or not reported | 42 |
| Irish | 17 |
| Norwegian | 15 |
| Other groups | 12 |
| English | 8 |
| Dutch | 5 |
| Swedish | 2 |
| Italian | 2 |
| Greek | 2 |
Language
| English Only | 107 |
| Spanish | 0 |
| Population 5+ | 107 |
Veterans
| Veterans | 8 |
| Population 18+ | 122 |
Source: Census ACS 5-Year 2023; Census ACS 5-Year 2023, Table B01003; Census ACS 5-Year 2023, B19013. Data for St. Marys, Iowa.