# Counties in South Dakota by median age on 1 July (US county estimates), 2025

All 66 values come from U.S. Census Bureau for 2025, so the places are comparable.

- Indicator id: `median_age_pep`
- Unit: years
- Definition: Age that divides the resident population of a US county into two halves of equal size on 1 July, from Census Bureau population estimates calculated by single year of age.
- Source: U.S. Census Bureau, Population Estimates Program, county population by age and sex: median age (MEDIAN_AGE_TOT) on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage (https://www.census.gov/programs-surveys/popest/data/data-sets.html)
- Publisher page: https://invokely.ai/en/publishers/us-census-bureau
- Retrieved: 2026-10-12
- Citation: U.S. Census Bureau. Population Estimates Program, county population by age and sex: median age (MEDIAN_AGE_TOT) on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage. https://www.census.gov/programs-surveys/popest/data/data-sets.html. Retrieved 2026-10-12.
- Web page: https://invokely.ai/rankings/median-age-july-1-us-counties/south-dakota-counties

| Rank | Place | years |
|---:|---|---:|
| 1 | Custer County | 57.2 |
| 2 | Fall River County | 56.1 |
| 3 | Potter County | 52.4 |
| 4 | McPherson County | 51.1 |
| 5 | Campbell County | 49.3 |
| 6 | Perkins County | 47 |
| 7 | Lawrence County | 46.4 |
| 7 | Sully County | 46.4 |
| 9 | Day County | 46.3 |
| 9 | Miner County | 46.3 |
| 11 | Gregory County | 45.8 |
| 11 | Jerauld County | 45.8 |
| 13 | Edmunds County | 45.5 |
| 14 | Hand County | 44.4 |
| 15 | Grant County | 44.3 |
| 16 | Haakon County | 44 |
| 17 | Spink County | 43.8 |
| 17 | Stanley County | 43.8 |
| 19 | Yankton County | 43.5 |
| 20 | Kingsbury County | 43.2 |
| 21 | Walworth County | 43.1 |
| 22 | Harding County | 42.5 |
| 23 | Brule County | 42.4 |
| 23 | Jones County | 42.4 |
| 25 | Hyde County | 42.3 |
| 25 | Union County | 42.3 |
| 27 | Deuel County | 42.2 |
| 27 | Douglas County | 42.2 |
| 27 | Marshall County | 42.2 |
| 30 | Bon Homme County | 42 |
| 31 | Lake County | 41.5 |
| 32 | Butte County | 41.4 |
| 33 | Davison County | 41.3 |
| 34 | Aurora County | 41.2 |
| 35 | Hutchinson County | 41.1 |
| 35 | Tripp County | 41.1 |
| 37 | Sanborn County | 41 |
| 38 | Hughes County | 40.7 |
| 39 | Codington County | 40.3 |
| 40 | McCook County | 40.2 |
| 41 | Faulk County | 40.1 |
| 42 | Moody County | 40 |
| 43 | Brown County | 39.8 |
| 44 | Pennington County | 39.6 |
| 44 | Turner County | 39.6 |
| 46 | Roberts County | 39.3 |
| 47 | Meade County | 39 |
| 48 | Hanson County | 38.7 |
| 49 | Clark County | 38.1 |
| 50 | Charles Mix County | 37 |
| 51 | Lincoln County | 36.8 |
| 52 | Minnehaha County | 36.4 |
| 53 | Beadle County | 36.2 |
| 54 | Lyman County | 35.9 |
| 55 | Bennett County | 32.6 |
| 56 | Hamlin County | 30.4 |
| 57 | Jackson County | 30.3 |
| 58 | Ziebach County | 29.8 |
| 59 | Brookings County | 29.1 |
| 60 | Corson County | 28.7 |
| 61 | Buffalo County | 26.7 |
| 62 | Dewey County | 26.2 |
| 62 | Oglala Lakota County | 26.2 |
| 64 | Todd County | 26 |
| 65 | Clay County | 25.7 |
| 66 | Mellette County | 25.3 |