Demographics & People — Jefferson, South Dakota
Population Overview
| Population (Census) | 717 |
| Estimated 2026 | ~300 |
| Median Age | 40.6 |
| Total Households | 316 |
| Family Households | 200 |
| Average Household Size | 2.27 |
| Diversity Index | N/A (N/A) |
Race & Ethnicity
| White | 647 |
| Black or African American | 0 |
| Asian | 0 |
| Hispanic or Latino | 46 |
Heritage & Ancestry
| Group | Count |
| Unclassified or not reported | 199 |
| German | 165 |
| American | 70 |
| Irish | 56 |
| French (except Basque) | 51 |
| French Canadian | 45 |
| Other groups | 44 |
| Norwegian | 42 |
| Swedish | 28 |
| Czech | 26 |
Language
| English Only | 645 |
| Spanish | 39 |
| Population 5+ | 686 |
Veterans
| Veterans | 59 |
| Population 18+ | 471 |
Source: Census ACS 5-Year 2023; Census ACS 5-Year 2023, Table B01003; Census ACS 5-Year 2023, B19013. Data for Jefferson, South Dakota.