| Place Name | St. Marie |
| Place Type | Census Designated Place |
| ZIP Code(s) | 59230 59231 59244 59248 |
| County | Valley County |
| Area Code(s) | 406 |
| Timezone | Mountain Standard Time (MST) |
| Population (2022) | 303 |
| Population Growth Rate (2010-19) | 85.23% |
| Majority Ethnicity | White 90.7% |
| US Congressional District(s) | Montana At-Large |
| State House Districts | 34 |
| State Senate Districts | 17 |
| Race/Ethnicy | Percentage of Population (2021) |
|---|---|
| White | 90.7% |
| African American | 0% |
| Hispanic | 9.3% |
| Asian | 0% |
| Native American | 0% |
| Hawaiin/Pacific Islander | 0% |