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

Custer County had the highest median age on 1 July (US county estimates) of 66 counties in 2021, at 56.4 years. Todd County had the lowest, at 24.2 years. The median was 41.5 years. Source: the U.S. Census Bureau.

Highest56.4Custer County

Lowest24.2Todd County

Median41.566 counties

Map of counties, 2021

Under 33
33 to 39
39 to 41
41 to 43
43 to 46
46 and over

years, 2021. 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. Boundaries: U.S. Census Bureau cartographic boundary files.

Top 40 counties, 2021

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	2021 years	Change on 2020
1	Custer County	56.4	-0.1
2	Fall River County	55.1	-0.2
3	Campbell County	53.4	-0.6
4	Potter County	52.2	-0.7
5	McPherson County	51.3	-0.2
6	Jerauld County	49	-0.2
7	Day County	47.3	-0.1
7	Gregory County	47.3	-0.3
9	Hand County	47.1	-0.3
10	Perkins County	46.9	-0.5
11	Douglas County	46.3	-1.5
12	Jones County	45.8	0
13	Hyde County	45.4	-1.3
14	Grant County	45.3	-0.3
14	Sully County	45.3	0
16	Miner County	45	-1.1
17	Haakon County	44.7	+0.2
18	Edmunds County	44.4	-0.7
18	Faulk County	44.4	-1.5
20	Kingsbury County	44.3	-0.7
21	Lawrence County	44	+0.3
22	Walworth County	43.5	-0.1
23	Spink County	43.3	+0.1
23	Tripp County	43.3	+0.1
25	Deuel County	43.2	-0.2
26	Bon Homme County	42.7	-0.7
27	Brule County	42.5	-0.2
27	Yankton County	42.5	+0.2
29	Aurora County	42	-0.1
30	Hutchinson County	41.9	-0.3
31	Marshall County	41.8	-0.2
31	Turner County	41.8	-0.5
33	Harding County	41.5	-0.4
34	Union County	41.4	+0.4
35	Stanley County	41.3	-0.6
36	McCook County	41.2	-0.6
37	Sanborn County	41.1	0
38	Butte County	40.9	-0.3
39	Moody County	40.8	-0.2
40	Lake County	40.6	+0.7
41	Davison County	40.1	+0.4
42	Hanson County	39.9	+0.3
43	Hughes County	39.7	+0.3
44	Codington County	39.5	+0.3
45	Roberts County	39.3	+0.2
46	Clark County	39.1	-0.3
47	Pennington County	38.9	+0.2
48	Brown County	38.4	+0.3
49	Meade County	37.4	0
50	Charles Mix County	37	+0.4
51	Beadle County	36.2	+0.1
52	Minnehaha County	36.1	+0.2
53	Lincoln County	35.6	+0.3
53	Lyman County	35.6	-0.5
55	Hamlin County	33.3	-1.5
56	Bennett County	32.5	0
56	Mellette County	32.5	-0.9
58	Corson County	30.3	-0.1
59	Dewey County	30.2	-0.5
60	Ziebach County	30.1	-0.2
61	Jackson County	29.8	-1.8
62	Brookings County	29.4	0
63	Buffalo County	25.5	-0.9
64	Oglala Lakota County	25.3	-0.1
65	Clay County	25.1	+0.1
66	Todd County	24.2	-0.1

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), 2021) [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), 2021. 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?period=2021. 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), 2021. 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?period=2021.

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), 2021 [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?period=2021 (Accessed: 12 October 2026).

BibTeX

@misc{census_counties_in_south_dakota_2021,
  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), 2021}},
  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?period=2021. 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), 2021
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?period=2021
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/median-age-july-1-us-counties/south-dakota-counties?period=2021.
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?period=2021" width="760" height="500" title="Counties in South Dakota by median age on 1 July (US county estimates), 2021, 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 56.4 years in 2021, according to the U.S. Census Bureau.

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

Todd County, with 24.2 years in 2021.

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.