| Place Name | Roundup |
| Place Type | City |
| ZIP Code(s) | 59072 |
| County | Musselshell County |
| Area Code(s) | 406 |
| Timezone | Mountain Standard Time (MST) |
| Population (2022) | 1,825 |
| Population Growth Rate (2010-19) | -2.57% |
| Majority Ethnicity | White 92.21% |
| US Congressional District(s) | Montana At-Large |
| State House Districts | 40 |
| State Senate Districts | 20 |
| Race/Ethnicy | Percentage of Population (2021) |
|---|---|
| White | 92.21% |
| African American | 0% |
| Hispanic | 1.51% |
| Asian | 0% |
| Native American | 0% |
| Hawaiin/Pacific Islander | 6.28% |