Data / Rankings / Population under 18 / Counties in South Dakota

Counties in South Dakota by population under 18

Todd County had the highest population under 18 of 66 counties in 2020, at 40.8%. Custer County had the lowest, at 16.7%. The median was 23.8% and the figure for South Dakota was 24.6%. Source: the U.S. Census Bureau.

Highest40.8Todd County
Lowest16.7Custer County
Median23.866 counties
South Dakota24.6History

Top 40 counties, 2020

Todd County: 40.8 %Todd County40.8Buffalo County: 38.1 %Buffalo County38.1Oglala Lakota County: 37.5 %Oglala Lakota County37.5Corson County: 34.9 %Corson County34.9Jackson County: 34.7 %Jackson County34.7Dewey County: 34.4 %Dewey County34.4Hamlin County: 32.5 %Hamlin County32.5Bennett County: 32.4 %Bennett County32.4Mellette County: 32.2 %Mellette County32.2Ziebach County: 32.1 %Ziebach County32.1Charles Mix County: 29.4 %Charles Mix County29.4Lyman County: 29.2 %Lyman County29.2Hanson County: 28.9 %Hanson County28.9Roberts County: 28.6 %Roberts County28.6Beadle County: 27.9 %Beadle County27.9Lincoln County: 27.8 %Lincoln County27.8Clark County: 27.4 %Clark County27.4Moody County: 26.8 %Moody County26.8Aurora County: 26 %Aurora County26McCook County: 25.9 %McCook County25.9Hutchinson County: 25.8 %Hutchinson County25.8Turner County: 25.4 %Turner County25.4Stanley County: 25.3 %Stanley County25.3Minnehaha County: 25.2 %Minnehaha County25.2Jones County: 25.1 %Jones County25.1Butte County: 25 %Butte County25Marshall County: 25 %Marshall County25Union County: 24.8 %Union County24.8Tripp County: 24.1 %Tripp County24.1Hughes County: 24.1 %Hughes County24.1Brule County: 24.1 %Brule County24.1Sanborn County: 23.8 %Sanborn County23.8Brown County: 23.8 %Brown County23.8Douglas County: 23.7 %Douglas County23.7Harding County: 23.6 %Harding County23.6Deuel County: 23.6 %Deuel County23.6Meade County: 23.6 %Meade County23.6Codington County: 23.5 %Codington County23.5Spink County: 23.5 %Spink County23.5Davison County: 23.2 %Davison County23.2
%. Source: Invokely calculation with data from U.S. Census Bureau. Retrieved 2026-10-12.

Full ranking

RankCounties2020 (%)Change on 2019
1Todd County40.8+0.6 pts
2Buffalo County38.1-1.1 pts
3Oglala Lakota County37.5+0.3 pts
4Corson County34.9-0.9 pts
5Jackson County34.7+2 pts
6Dewey County34.4+2 pts
7Hamlin County32.5+0.4 pts
8Bennett County32.4-0.2 pts
9Mellette County32.20 pts
10Ziebach County32.1-2.8 pts
11Charles Mix County29.4+0.6 pts
12Lyman County29.2-0.8 pts
13Hanson County28.9-1.1 pts
14Roberts County28.6+0.4 pts
15Beadle County27.9+0.7 pts
16Lincoln County27.8-0.7 pts
17Clark County27.4+0.6 pts
18Moody County26.8+0.2 pts
19Aurora County26+0.8 pts
20McCook County25.9+0.4 pts
21Hutchinson County25.8+0.7 pts
22Turner County25.4-0 pts
23Stanley County25.3+0.1 pts
24Minnehaha County25.2+0.1 pts
25Jones County25.1+3 pts
26Butte County25+1.1 pts
27Marshall County25+1.5 pts
28Union County24.80 pts
29Tripp County24.1+0.3 pts
30Hughes County24.1+0.3 pts
31Brule County24.1+0.7 pts
32Sanborn County23.8-0.9 pts
33Brown County23.8+0.3 pts
34Douglas County23.7+0.6 pts
35Harding County23.6-1.2 pts
36Deuel County23.6+0.5 pts
37Meade County23.6-1.7 pts
38Codington County23.5-0.1 pts
39Spink County23.5-0.1 pts
40Davison County23.2+0.4 pts
41Gregory County23+0.6 pts
42Jerauld County23-0.2 pts
43Day County23-0.2 pts
43Pennington County23+0.3 pts
45Kingsbury County23-0.1 pts
46Haakon County23-0.3 pts
47Walworth County22.8-0.1 pts
48Faulk County22.7+0.4 pts
49Miner County22.7-0.2 pts
50Lake County22+0.2 pts
51Grant County22-0.7 pts
52Edmunds County22-1 pts
53Hand County21.5+0.1 pts
54Hyde County21.4+1.9 pts
55Perkins County21.4+0.4 pts
56Brookings County21.2+0.3 pts
57Yankton County21.1-0.1 pts
58Sully County21+0.1 pts
59McPherson County20-1.7 pts
60Campbell County19.4-0.8 pts
61Potter County19.4-0 pts
62Lawrence County18.7-0.3 pts
63Bon Homme County18.3-0.4 pts
64Clay County17.2+0.1 pts
65Fall River County16.8-0.3 pts
66Custer County16.7-0.1 pts

Other periods

About this ranking

Residents aged 0 to 17 as a percentage of total population on 1 July. United States: Census Bureau county population estimates by age; states and the nation are sums of their counties.

Uses the US age of majority. Not comparable with population_0_14_share, which stops at 14.

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: residents aged 0 to 17 as a percentage of the total on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage; states and the nation summed from counties. 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: residents aged 0 to 17 as a percentage of the total on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage; states and the nation summed from counties (Counties in South Dakota by population under 18, 2020) [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: residents aged 0 to 17 as a percentage of the total on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage; states and the nation summed from counties, Counties in South Dakota by population under 18, 2020. U.S. Census Bureau, 25 June 2026, https://www.census.gov/programs-surveys/popest/data/data-sets.html. Invokely, https://invokely.ai/rankings/population-under-18/south-dakota-counties?period=2020. Accessed 12 Oct. 2026.

Chicago (author-date)

U.S. Census Bureau. 2026. Population Estimates Program, county population by age and sex: residents aged 0 to 17 as a percentage of the total on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage; states and the nation summed from counties. Counties in South Dakota by population under 18, 2020. Dataset. Accessed October 12, 2026. https://www.census.gov/programs-surveys/popest/data/data-sets.html. Also distributed by Invokely, https://invokely.ai/rankings/population-under-18/south-dakota-counties?period=2020.

Harvard

U.S. Census Bureau (2026) Population Estimates Program, county population by age and sex: residents aged 0 to 17 as a percentage of the total on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage; states and the nation summed from counties, Counties in South Dakota by population under 18, 2020 [Dataset]. Available at: https://www.census.gov/programs-surveys/popest/data/data-sets.html, via Invokely: https://invokely.ai/rankings/population-under-18/south-dakota-counties?period=2020 (Accessed: 12 October 2026).

BibTeX
@misc{census_counties_in_south_dakota_2020,
  author = {{U.S. Census Bureau}},
  title = {{Population Estimates Program, county population by age and sex: residents aged 0 to 17 as a percentage of the total on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage; states and the nation summed from counties: Counties in South Dakota by population under 18, 2020}},
  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/population-under-18/south-dakota-counties?period=2020. Publisher attribution: U.S. Census Bureau. Population Estimates Program, county population by age and sex: residents aged 0 to 17 as a percentage of the total on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage; states and the nation summed from counties. 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: residents aged 0 to 17 as a percentage of the total on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage; states and the nation summed from counties: Counties in South Dakota by population under 18, 2020
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/population-under-18/south-dakota-counties?period=2020
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/population-under-18/south-dakota-counties?period=2020.
N1  - Publisher attribution: U.S. Census Bureau. Population Estimates Program, county population by age and sex: residents aged 0 to 17 as a percentage of the total on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage; states and the nation summed from counties. 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.

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 population under 18 using official data, and cite the source.
rank_places {"indicator":"population_0_17_share","level":"province","within":"South Dakota","limit":10}
GET https://invokely.ai/api/v1/rank?indicator=population_0_17_share&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 population under 18?

Todd County, with 40.8% in 2020, according to the U.S. Census Bureau.

Which county has the lowest population under 18?

Custer County, with 16.7% in 2020.

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: residents aged 0 to 17 as a percentage of the total on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage; states and the nation summed from counties. Retrieved 2026-10-12.

Population under 18: other rankings

Counties in South Dakota: more rankings