| Place Name | Eureka |
| Place Type | Town |
| ZIP Code(s) | 59917 |
| County | Lincoln County |
| Area Code(s) | 406 |
| Timezone | Mountain Daylight Time (MDT) |
| Population (2022) | 1,123 |
| Population Growth Rate (2010-19) | 33.08% |
| Majority Ethnicity | White 90.55% |
| US Congressional District(s) | Montana At-Large |
| State House Districts | 2 |
| State Senate Districts | 1 |
| Race/Ethnicy | Percentage of Population (2021) |
|---|---|
| White | 90.55% |
| African American | 0% |
| Hispanic | 2.97% |
| Asian | 0% |
| Native American | 0% |
| Hawaiin/Pacific Islander | 6.48% |