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 2021, at 40.6%. Fall River County had the lowest, at 16.6%. The median was 24% and the figure for South Dakota was 24.5%. Source: the U.S. Census Bureau.

Highest40.6Todd County
Lowest16.6Fall River County
Median2466 counties
South Dakota24.5History

Top 40 counties, 2021

Todd County: 40.6 %Todd County40.6Buffalo County: 37.8 %Buffalo County37.8Oglala Lakota County: 37.3 %Oglala Lakota County37.3Jackson County: 36 %Jackson County36Corson County: 35.4 %Corson County35.4Dewey County: 34.9 %Dewey County34.9Hamlin County: 33.2 %Hamlin County33.2Mellette County: 33 %Mellette County33Ziebach County: 32.3 %Ziebach County32.3Bennett County: 31.4 %Bennett County31.4Charles Mix County: 29.1 %Charles Mix County29.1Lyman County: 29 %Lyman County29Hanson County: 28.9 %Hanson County28.9Roberts County: 28.4 %Roberts County28.4Clark County: 27.9 %Clark County27.9Beadle County: 27.9 %Beadle County27.9Lincoln County: 27.3 %Lincoln County27.3Moody County: 26.7 %Moody County26.7McCook County: 26 %McCook County26Hutchinson County: 25.7 %Hutchinson County25.7Marshall County: 25.7 %Marshall County25.7Turner County: 25.6 %Turner County25.6Aurora County: 25.5 %Aurora County25.5Stanley County: 25.1 %Stanley County25.1Jones County: 25.1 %Jones County25.1Minnehaha County: 25.1 %Minnehaha County25.1Butte County: 24.9 %Butte County24.9Harding County: 24.5 %Harding County24.5Douglas County: 24.3 %Douglas County24.3Union County: 24.2 %Union County24.2Sanborn County: 24.1 %Sanborn County24.1Tripp County: 24.1 %Tripp County24.1Hughes County: 24 %Hughes County24Deuel County: 23.9 %Deuel County23.9Kingsbury County: 23.7 %Kingsbury County23.7Brule County: 23.6 %Brule County23.6Brown County: 23.5 %Brown County23.5Spink County: 23.3 %Spink County23.3Gregory County: 23.3 %Gregory County23.3Codington County: 23.2 %Codington County23.2
%. Source: Invokely calculation with data from U.S. Census Bureau. Retrieved 2026-10-12.

Full ranking

RankCounties2021 (%)Change on 2020
1Todd County40.6-0.2 pts
2Buffalo County37.8-0.2 pts
3Oglala Lakota County37.3-0.2 pts
4Jackson County36+1.3 pts
5Corson County35.4+0.5 pts
6Dewey County34.9+0.5 pts
7Hamlin County33.2+0.7 pts
8Mellette County33+0.8 pts
9Ziebach County32.3+0.2 pts
10Bennett County31.4-1 pts
11Charles Mix County29.1-0.3 pts
12Lyman County29-0.2 pts
13Hanson County28.9+0.1 pts
14Roberts County28.4-0.2 pts
15Clark County27.9+0.6 pts
16Beadle County27.90 pts
17Lincoln County27.3-0.5 pts
18Moody County26.7-0.1 pts
19McCook County26+0.2 pts
20Hutchinson County25.7-0.1 pts
21Marshall County25.7+0.7 pts
22Turner County25.6+0.2 pts
23Aurora County25.5-0.4 pts
24Stanley County25.1-0.2 pts
25Jones County25.1-0.1 pts
25Minnehaha County25.1-0.2 pts
27Butte County24.9-0.1 pts
28Harding County24.5+0.8 pts
29Douglas County24.3+0.5 pts
30Union County24.2-0.6 pts
31Sanborn County24.1+0.3 pts
32Tripp County24.1-0 pts
33Hughes County24-0.1 pts
34Deuel County23.9+0.4 pts
35Kingsbury County23.7+0.7 pts
36Brule County23.6-0.5 pts
37Brown County23.5-0.3 pts
38Spink County23.3-0.2 pts
39Gregory County23.3+0.3 pts
40Codington County23.2-0.3 pts
41Miner County23.2+0.5 pts
42Meade County23.1-0.4 pts
43Faulk County23.1+0.4 pts
44Davison County23.1-0.1 pts
45Pennington County22.8-0.2 pts
46Edmunds County22.6+0.6 pts
47Day County22.5-0.4 pts
48Haakon County22.5-0.4 pts
49Jerauld County22.5-0.5 pts
50Walworth County22.4-0.4 pts
51Grant County22.1+0.1 pts
52Hyde County21.8+0.4 pts
53Hand County21.6+0.1 pts
54Lake County21.5-0.5 pts
55Brookings County21.20 pts
56Perkins County21.1-0.2 pts
57Yankton County21.10 pts
58Sully County20.7-0.3 pts
59Potter County19.6+0.3 pts
60McPherson County19.6-0.4 pts
61Campbell County19.6+0.1 pts
62Bon Homme County18.7+0.4 pts
63Lawrence County18.4-0.3 pts
64Clay County17.20 pts
65Custer County16.80 pts
66Fall River County16.6-0.2 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, 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: 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, 2021. 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=2021. 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, 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/population-under-18/south-dakota-counties?period=2021.

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, 2021 [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=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: 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, 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/population-under-18/south-dakota-counties?period=2021. 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, 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/population-under-18/south-dakota-counties?period=2021
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/population-under-18/south-dakota-counties?period=2021.
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  -
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Questions

Which county has the highest population under 18?

Todd County, with 40.6% in 2021, according to the U.S. Census Bureau.

Which county has the lowest population under 18?

Fall River County, with 16.6% 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: 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