| Place Name | Eureka |
| Place Type | City |
| ZIP Code(s) | 57437 |
| County | Mcpherson County |
| Area Code(s) | 605 |
| Timezone | Central Daylight Time (CDT) |
| Population (2022) | 883 |
| Population Growth Rate (2010-19) | -6.34% |
| Majority Ethnicity | White 95.29% |
| US Congressional District(s) | South Dakota At-Large |
| State House Districts | 23 |
| State Senate Districts | 23 |
| Race/Ethnicy | Percentage of Population (2021) |
|---|---|
| White | 95.29% |
| African American | 3.45% |
| Hispanic | 0.23% |
| Asian | 0.69% |
| Native American | 0.11% |
| Hawaiin/Pacific Islander | 0.23% |