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

Custer County had the highest median age on 1 July (US county estimates) of 66 counties in 2025, at 57.2 years. Mellette County had the lowest, at 25.3 years. The median was 41.3 years. Source: the U.S. Census Bureau.

Highest57.2Custer County

Lowest25.3Mellette County

Median41.366 counties

Top 40 counties, 2025

years. 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. Retrieved 2026-10-12.

Full ranking

Rank	Counties	2025 years	Change on 2024
1	Custer County	57.2	+0.5
2	Fall River County	56.1	-0.2
3	Potter County	52.4	-0.6
4	McPherson County	51.1	+0.2
5	Campbell County	49.3	-2.1
6	Perkins County	47	+0.3
7	Lawrence County	46.4	+0.5
7	Sully County	46.4	+0.3
9	Day County	46.3	-0.3
9	Miner County	46.3	+0.1
11	Gregory County	45.8	0
11	Jerauld County	45.8	-0.5
13	Edmunds County	45.5	+0.8
14	Hand County	44.4	-0.6
15	Grant County	44.3	+0.1
16	Haakon County	44	-0.1
17	Spink County	43.8	+0.2
17	Stanley County	43.8	+0.5
19	Yankton County	43.5	+0.1
20	Kingsbury County	43.2	-0.3
21	Walworth County	43.1	+0.1
22	Harding County	42.5	-0.1
23	Brule County	42.4	0
23	Jones County	42.4	-1.9
25	Hyde County	42.3	-1.2
25	Union County	42.3	+0.3
27	Deuel County	42.2	-0.2
27	Douglas County	42.2	-0.7
27	Marshall County	42.2	+0.7
30	Bon Homme County	42	-0.1
31	Lake County	41.5	+0.3
32	Butte County	41.4	+0.5
33	Davison County	41.3	+0.1
34	Aurora County	41.2	+0.1
35	Hutchinson County	41.1	0
35	Tripp County	41.1	+0.2
37	Sanborn County	41	-0.1
38	Hughes County	40.7	+0.2
39	Codington County	40.3	+0.1
40	McCook County	40.2	-0.4
41	Faulk County	40.1	-1.5
42	Moody County	40	-0.2
43	Brown County	39.8	+0.2
44	Pennington County	39.6	-0.1
44	Turner County	39.6	-0.5
46	Roberts County	39.3	+0.3
47	Meade County	39	+0.6
48	Hanson County	38.7	+0.1
49	Clark County	38.1	0
50	Charles Mix County	37	-0.1
51	Lincoln County	36.8	+0.3
52	Minnehaha County	36.4	0
53	Beadle County	36.2	0
54	Lyman County	35.9	-0.1
55	Bennett County	32.6	+0.3
56	Hamlin County	30.4	-0.4
57	Jackson County	30.3	+0.1
58	Ziebach County	29.8	-0.8
59	Brookings County	29.1	+0.1
60	Corson County	28.7	-0.4
61	Buffalo County	26.7	+0.9
62	Dewey County	26.2	-0.8
62	Oglala Lakota County	26.2	+0.2
64	Todd County	26	+0.5
65	Clay County	25.7	+0.2
66	Mellette County	25.3	-3.4

Other periods

About this ranking

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.

Counties only: the county file has no state or national medians, and medians cannot be added up. A single-year estimate, unlike median_age, which for US places is a five-year American Community Survey estimate.

Every value in the ranking comes from the same publisher and the same period, so the counties are compared on one definition. Equal values share a rank.

How to cite

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.

Citation styles

The publisher is the author. Invokely is named only as the place the figures were read, where a style asks for it.

APA 7

U.S. Census Bureau. (2026). 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 (Counties in South Dakota by median age on 1 July (US county estimates), 2025) [Data set]. Retrieved October 12, 2026, from https://www.census.gov/programs-surveys/popest/data/data-sets.html

MLA 9

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, Counties in South Dakota by median age on 1 July (US county estimates), 2025. U.S. Census Bureau, 25 June 2026, https://www.census.gov/programs-surveys/popest/data/data-sets.html. Invokely, https://invokely.ai/rankings/median-age-july-1-us-counties/south-dakota-counties. Accessed 12 Oct. 2026.

Chicago (author-date)

U.S. Census Bureau. 2026. 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. Counties in South Dakota by median age on 1 July (US county estimates), 2025. Dataset. Accessed October 12, 2026. https://www.census.gov/programs-surveys/popest/data/data-sets.html. Also distributed by Invokely, https://invokely.ai/rankings/median-age-july-1-us-counties/south-dakota-counties.

Harvard

U.S. Census Bureau (2026) 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, Counties in South Dakota by median age on 1 July (US county estimates), 2025 [Dataset]. Available at: https://www.census.gov/programs-surveys/popest/data/data-sets.html, via Invokely: https://invokely.ai/rankings/median-age-july-1-us-counties/south-dakota-counties (Accessed: 12 October 2026).

BibTeX

@misc{census_counties_in_south_dakota_2025,
  author = {{U.S. Census Bureau}},
  title = {{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: Counties in South Dakota by median age on 1 July (US county estimates), 2025}},
  year = {2026},
  howpublished = {Data set},
  url = {https://www.census.gov/programs-surveys/popest/data/data-sets.html},
  urldate = {2026-10-12},
  note = {Accessed via Invokely, https://invokely.ai/rankings/median-age-july-1-us-counties/south-dakota-counties. Publisher attribution: 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.},
}

RIS

TY  - DATA
AU  - U.S. Census Bureau
TI  - 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: Counties in South Dakota by median age on 1 July (US county estimates), 2025
PY  - 2026
DA  - 2026/06/25
PB  - U.S. Census Bureau
DB  - Invokely
UR  - https://www.census.gov/programs-surveys/popest/data/data-sets.html
L2  - https://invokely.ai/rankings/median-age-july-1-us-counties/south-dakota-counties
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/median-age-july-1-us-counties/south-dakota-counties.
N1  - Publisher attribution: 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.
ER  -

Embed this chart

Paste this code into a web page or a blog post. The chart shows the latest figures as they are published, with the source and a link back to this page.

Embed code

<iframe src="https://invokely.ai/embed/rankings/median-age-july-1-us-counties/south-dakota-counties" width="760" height="500" title="Counties in South Dakota by median age on 1 July (US county estimates), 2025, chart from Invokely" loading="lazy" style="border:0;width:100%;max-width:760px" referrerpolicy="strict-origin-when-cross-origin"></iframe>

Sites that read oEmbed links, such as WordPress, can show the chart when you paste the link to this page.

Use this data in your AI agent

Invokely serves this figure to AI assistants through MCP and to code through a REST API, with the source and citation attached. Ask your assistant:

Rank Counties in South Dakota by median age on 1 July (US county estimates) using official data, and cite the source.

rank_places {"indicator":"median_age_pep","level":"province","within":"South Dakota","limit":10}
GET https://invokely.ai/api/v1/rank?indicator=median_age_pep&level=province&within=South%20Dakota&limit=10

Connect Claude, ChatGPT or Cursor in one step. The trial answers 25 calls a day without an account.

Questions

Which county has the highest median age on 1 July (US county estimates)?

Custer County, with 57.2 years in 2025, according to the U.S. Census Bureau.

Which county has the lowest median age on 1 July (US county estimates)?

Mellette County, with 25.3 years in 2025.

Where does this ranking come from?

Every value comes from one source and one period, so the places are comparable: 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. Retrieved 2026-10-12.