| Place Name | Keystone |
| Place Type | Town |
| ZIP Code(s) | 57751 |
| County | Pennington County |
| Area Code(s) | 605 |
| Timezone | Mountain Daylight Time (MDT) |
| Population (2022) | 397 |
| Population Growth Rate (2010-19) | -28.78% |
| Majority Ethnicity | White 77.67% |
| Metro/Micro Stats Area | Rapid City, SD |
| US Congressional District(s) | South Dakota At-Large |
| State House Districts | 30 |
| State Senate Districts | 30 |
| Race/Ethnicy | Percentage of Population (2021) |
|---|---|
| White | 77.67% |
| African American | 0% |
| Hispanic | 1.5% |
| Asian | 1.31% |
| Native American | 0% |
| Hawaiin/Pacific Islander | 19.51% |