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 2018, at 40.6%. Custer County had the lowest, at 16.7%. The median was 23.6% and the figure for South Dakota was 24.7%. Source: the U.S. Census Bureau.

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Highest40.6Todd County
Lowest16.7Custer County
Median23.666 counties
South Dakota24.7History

Map of counties, 2018

Aurora County: 25.6 %Beadle County: 27 %Bennett County: 33 %Bon Homme County: 18.9 %Brookings County: 20.7 %Brown County: 23.8 %Brule County: 23.6 %Buffalo County: 39.2 %Butte County: 23.5 %Campbell County: 18.8 %Charles Mix County: 29 %Clark County: 26.3 %Clay County: 17.1 %Codington County: 23.9 %Corson County: 36.6 %Custer County: 16.7 %Davison County: 22.7 %Day County: 23.3 %Deuel County: 23.3 %Dewey County: 33 %Douglas County: 23.3 %Edmunds County: 23.3 %Fall River County: 17.3 %Faulk County: 22.7 %Grant County: 22.7 %Gregory County: 22.7 %Haakon County: 23.9 %Hamlin County: 31.3 %Hand County: 21.8 %Hanson County: 30.3 %Harding County: 24.6 %Hughes County: 23.6 %Hutchinson County: 24.9 %Hyde County: 19.9 %Jackson County: 31.4 %Jerauld County: 23.8 %Jones County: 22.8 %Kingsbury County: 22.6 %Lake County: 21.5 %Lawrence County: 19.1 %Lincoln County: 28.7 %Lyman County: 29.9 %McCook County: 25.6 %McPherson County: 21.9 %Marshall County: 23.3 %Meade County: 25.4 %Mellette County: 32.4 %Miner County: 23.1 %Minnehaha County: 25.2 %Moody County: 26 %Oglala Lakota County: 37.8 %Pennington County: 23 %Perkins County: 20.8 %Potter County: 20.1 %Roberts County: 28.1 %Sanborn County: 24.9 %Spink County: 23.3 %Stanley County: 24.4 %Sully County: 20.5 %Todd County: 40.6 %Tripp County: 23.4 %Turner County: 25.4 %Union County: 24.7 %Walworth County: 22.7 %Yankton County: 21.2 %Ziebach County: 35 %
  • Under 21
  • 21 to 23
  • 23 to 24
  • 24 to 25
  • 25 to 30
  • 30 and over
%, 2018. Source: Invokely calculation with data from U.S. Census Bureau. Boundaries: U.S. Census Bureau cartographic boundary files.

Top 40 counties, 2018

Todd County: 40.6 %Todd County40.6Buffalo County: 39.2 %Buffalo County39.2Oglala Lakota County: 37.8 %Oglala Lakota County37.8Corson County: 36.6 %Corson County36.6Ziebach County: 35 %Ziebach County35Dewey County: 33 %Dewey County33Bennett County: 33 %Bennett County33Mellette County: 32.4 %Mellette County32.4Jackson County: 31.4 %Jackson County31.4Hamlin County: 31.3 %Hamlin County31.3Hanson County: 30.3 %Hanson County30.3Lyman County: 29.9 %Lyman County29.9Charles Mix County: 29 %Charles Mix County29Lincoln County: 28.7 %Lincoln County28.7Roberts County: 28.1 %Roberts County28.1Beadle County: 27 %Beadle County27Clark County: 26.3 %Clark County26.3Moody County: 26 %Moody County26McCook County: 25.6 %McCook County25.6Aurora County: 25.6 %Aurora County25.6Turner County: 25.4 %Turner County25.4Meade County: 25.4 %Meade County25.4Minnehaha County: 25.2 %Minnehaha County25.2Sanborn County: 24.9 %Sanborn County24.9Hutchinson County: 24.9 %Hutchinson County24.9Union County: 24.7 %Union County24.7Harding County: 24.6 %Harding County24.6Stanley County: 24.4 %Stanley County24.4Codington County: 23.9 %Codington County23.9Haakon County: 23.9 %Haakon County23.9Brown County: 23.8 %Brown County23.8Jerauld County: 23.8 %Jerauld County23.8Hughes County: 23.6 %Hughes County23.6Brule County: 23.6 %Brule County23.6Butte County: 23.5 %Butte County23.5Tripp County: 23.4 %Tripp County23.4Day County: 23.3 %Day County23.3Spink County: 23.3 %Spink County23.3Douglas County: 23.3 %Douglas County23.3Marshall County: 23.3 %Marshall County23.3Todd County: 40.6 %Todd County40.6Buffalo County: 39.2 %Buffalo County39.2Oglala Lakota County: 37.8 %Oglala Lakota County37.8Corson County: 36.6 %Corson County36.6Ziebach County: 35 %Ziebach County35Dewey County: 33 %Dewey County33Bennett County: 33 %Bennett County33Mellette County: 32.4 %Mellette County32.4Jackson County: 31.4 %Jackson County31.4Hamlin County: 31.3 %Hamlin County31.3Hanson County: 30.3 %Hanson County30.3Lyman County: 29.9 %Lyman County29.9Charles Mix County: 29 %Charles Mix County29Lincoln County: 28.7 %Lincoln County28.7Roberts County: 28.1 %Roberts County28.1Beadle County: 27 %Beadle County27Clark County: 26.3 %Clark County26.3Moody County: 26 %Moody County26McCook County: 25.6 %McCook County25.6Aurora County: 25.6 %Aurora County25.6Turner County: 25.4 %Turner County25.4Meade County: 25.4 %Meade County25.4Minnehaha County: 25.2 %Minnehaha County25.2Sanborn County: 24.9 %Sanborn County24.9Hutchinson County: 24.9 %Hutchinson County24.9Union County: 24.7 %Union County24.7Harding County: 24.6 %Harding County24.6Stanley County: 24.4 %Stanley County24.4Codington County: 23.9 %Codington County23.9Haakon County: 23.9 %Haakon County23.9Brown County: 23.8 %Brown County23.8Jerauld County: 23.8 %Jerauld County23.8Hughes County: 23.6 %Hughes County23.6Brule County: 23.6 %Brule County23.6Butte County: 23.5 %Butte County23.5Tripp County: 23.4 %Tripp County23.4Day County: 23.3 %Day County23.3Spink County: 23.3 %Spink County23.3Douglas County: 23.3 %Douglas County23.3Marshall County: 23.3 %Marshall County23.3
%. Source: Invokely calculation with data from U.S. Census Bureau. Retrieved 2026-10-12.

Full ranking

RankCounties2018 (%)Change on 2017
1Todd County40.6-0.4 pts
2Buffalo County39.2+0.1 pts
3Oglala Lakota County37.8-0.3 pts
4Corson County36.6+0.4 pts
5Ziebach County35-0.7 pts
6Dewey County33+0.4 pts
7Bennett County33+0.1 pts
8Mellette County32.4+0.5 pts
9Jackson County31.4-0.4 pts
10Hamlin County31.3-0.1 pts
11Hanson County30.3-0.5 pts
12Lyman County29.9-0.2 pts
13Charles Mix County290 pts
14Lincoln County28.7-0.3 pts
15Roberts County28.1+0.5 pts
16Beadle County270 pts
17Clark County26.3+0.7 pts
18Moody County260 pts
19McCook County25.6+0.1 pts
20Aurora County25.6-0.2 pts
21Turner County25.4+0.8 pts
22Meade County25.40 pts
23Minnehaha County25.2-0.1 pts
24Sanborn County24.9-0.9 pts
25Hutchinson County24.9+0.1 pts
26Union County24.7-0.1 pts
27Harding County24.6+0.1 pts
28Stanley County24.4-0.1 pts
29Codington County23.9-0.2 pts
30Haakon County23.9+0.1 pts
31Brown County23.8-0.2 pts
32Jerauld County23.8+0.3 pts
33Hughes County23.60 pts
34Brule County23.6-1.2 pts
35Butte County23.5-0.3 pts
36Tripp County23.4-0.1 pts
37Day County23.3+0.3 pts
38Spink County23.3-0.3 pts
39Douglas County23.3+0.2 pts
40Marshall County23.3+0.1 pts
41Edmunds County23.3-0 pts
42Deuel County23.3-0.1 pts
43Miner County23.1-0.4 pts
44Pennington County23-0.3 pts
45Jones County22.8-0.1 pts
46Davison County22.7-0.1 pts
47Walworth County22.7-0.4 pts
48Gregory County22.7+0.5 pts
49Faulk County22.7+0.9 pts
50Grant County22.7+0.1 pts
51Kingsbury County22.6+0.2 pts
52McPherson County21.9+0.2 pts
53Hand County21.8+0.4 pts
54Lake County21.5+0.2 pts
55Yankton County21.2-0.2 pts
56Perkins County20.8-0.4 pts
57Brookings County20.7+0.3 pts
58Sully County20.5-1.2 pts
59Potter County20.1+0.2 pts
60Hyde County19.9-0.7 pts
61Lawrence County19.1-0.1 pts
62Bon Homme County18.9+0.3 pts
63Campbell County18.8-0 pts
64Fall River County17.3-0.2 pts
65Clay County17.1-0.3 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, 2018) [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, 2018. 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=2018. 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, 2018. 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=2018.

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, 2018 [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=2018 (Accessed: 12 October 2026).

BibTeX
@misc{census_counties_in_south_dakota_2018,
  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, 2018}},
  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=2018. 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, 2018
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=2018
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/population-under-18/south-dakota-counties?period=2018.
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 2018, according to the U.S. Census Bureau.

Which county has the lowest population under 18?

Custer County, with 16.7% in 2018.

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