| Place Name | Plains |
| Place Type | Town |
| ZIP Code(s) | 59859 |
| County | Sanders County |
| Area Code(s) | 406 |
| Timezone | Mountain Daylight Time (MDT) |
| Population (2022) | 888 |
| Population Growth Rate (2010-19) | 5.53% |
| Majority Ethnicity | White 93.18% |
| US Congressional District(s) | Montana At-Large |
| State House Districts | 14 |
| State Senate Districts | 7 |
| Race/Ethnicy | Percentage of Population (2021) |
|---|---|
| White | 93.18% |
| African American | 0.71% |
| Hispanic | 4.34% |
| Asian | 0% |
| Native American | 0% |
| Hawaiin/Pacific Islander | 1.77% |