Data / Rankings / Population under 18 / Counties in Michigan

Counties in Michigan by population under 18

St. Joseph County had the highest population under 18 of 83 counties in 2021, at 24.4%. Ontonagon County had the lowest, at 11.8%. The median was 19.8% and the figure for Michigan was 21.3%. Source: the U.S. Census Bureau.

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Highest24.4St. Joseph County
Lowest11.8Ontonagon County
Median19.883 counties
Michigan21.3History

Map of counties, 2021

Alcona County: 13.2 %Alger County: 15.6 %Allegan County: 23.6 %Alpena County: 18.6 %Antrim County: 16.9 %Arenac County: 18.2 %Baraga County: 17.7 %Barry County: 22.2 %Bay County: 19.5 %Benzie County: 17.1 %Berrien County: 21.3 %Branch County: 23.9 %Calhoun County: 22.9 %Cass County: 21 %Charlevoix County: 18 %Cheboygan County: 16.7 %Chippewa County: 19 %Clare County: 19.9 %Clinton County: 22 %Crawford County: 18.1 %Delta County: 19.4 %Dickinson County: 19.6 %Eaton County: 21 %Emmet County: 18.1 %Genesee County: 22.2 %Gladwin County: 18.8 %Gogebic County: 16.5 %Grand Traverse County: 19.5 %Gratiot County: 19.7 %Hillsdale County: 21.8 %Houghton County: 19.8 %Huron County: 18.7 %Ingham County: 20.8 %Ionia County: 21.3 %Iosco County: 17.1 %Iron County: 16.9 %Isabella County: 19.2 %Jackson County: 21.1 %Kalamazoo County: 21.8 %Kalkaska County: 20 %Kent County: 23.5 %Keweenaw County: 15.2 %Lake County: 15.7 %Lapeer County: 20.3 %Leelanau County: 16 %Lenawee County: 20.7 %Livingston County: 20.8 %Luce County: 17.2 %Mackinac County: 16.1 %Macomb County: 20.3 %Manistee County: 16.6 %Marquette County: 17.9 %Mason County: 19.8 %Mecosta County: 19.6 %Menominee County: 17.9 %Midland County: 21.3 %Missaukee County: 22.4 %Monroe County: 21 %Montcalm County: 21.1 %Montmorency County: 15.4 %Muskegon County: 22.5 %Newaygo County: 22.1 %Oakland County: 20.2 %Oceana County: 22.1 %Ogemaw County: 18.1 %Ontonagon County: 11.8 %Osceola County: 23.1 %Oscoda County: 18.8 %Otsego County: 20.4 %Ottawa County: 23.4 %Presque Isle County: 15.2 %Roscommon County: 14.5 %Saginaw County: 21.5 %St. Clair County: 20.3 %St. Joseph County: 24.4 %Sanilac County: 21.3 %Schoolcraft County: 17.4 %Shiawassee County: 20.6 %Tuscola County: 20.8 %Van Buren County: 22.9 %Washtenaw County: 18.2 %Wayne County: 23.3 %Wexford County: 23 %
  • Under 17
  • 17 to 18
  • 18 to 20
  • 20 to 21
  • 21 to 22
  • 22 and over
%, 2021. Source: Invokely calculation with data from U.S. Census Bureau. Boundaries: U.S. Census Bureau cartographic boundary files.

Top 40 counties, 2021

St. Joseph County: 24.4 %St. Joseph County24.4Branch County: 23.9 %Branch County23.9Allegan County: 23.6 %Allegan County23.6Kent County: 23.5 %Kent County23.5Ottawa County: 23.4 %Ottawa County23.4Wayne County: 23.3 %Wayne County23.3Osceola County: 23.1 %Osceola County23.1Wexford County: 23 %Wexford County23Van Buren County: 22.9 %Van Buren County22.9Calhoun County: 22.9 %Calhoun County22.9Muskegon County: 22.5 %Muskegon County22.5Missaukee County: 22.4 %Missaukee County22.4Barry County: 22.2 %Barry County22.2Genesee County: 22.2 %Genesee County22.2Newaygo County: 22.1 %Newaygo County22.1Oceana County: 22.1 %Oceana County22.1Clinton County: 22 %Clinton County22Hillsdale County: 21.8 %Hillsdale County21.8Kalamazoo County: 21.8 %Kalamazoo County21.8Saginaw County: 21.5 %Saginaw County21.5Berrien County: 21.3 %Berrien County21.3Ionia County: 21.3 %Ionia County21.3Sanilac County: 21.3 %Sanilac County21.3Midland County: 21.3 %Midland County21.3Montcalm County: 21.1 %Montcalm County21.1Jackson County: 21.1 %Jackson County21.1Cass County: 21 %Cass County21Monroe County: 21 %Monroe County21Eaton County: 21 %Eaton County21Livingston County: 20.8 %Livingston County20.8Ingham County: 20.8 %Ingham County20.8Tuscola County: 20.8 %Tuscola County20.8Lenawee County: 20.7 %Lenawee County20.7Shiawassee County: 20.6 %Shiawassee County20.6Otsego County: 20.4 %Otsego County20.4Macomb County: 20.3 %Macomb County20.3St. Clair County: 20.3 %St. Clair County20.3Lapeer County: 20.3 %Lapeer County20.3Oakland County: 20.2 %Oakland County20.2Kalkaska County: 20 %Kalkaska County20St. Joseph County: 24.4 %St. Joseph County24.4Branch County: 23.9 %Branch County23.9Allegan County: 23.6 %Allegan County23.6Kent County: 23.5 %Kent County23.5Ottawa County: 23.4 %Ottawa County23.4Wayne County: 23.3 %Wayne County23.3Osceola County: 23.1 %Osceola County23.1Wexford County: 23 %Wexford County23Van Buren County: 22.9 %Van Buren County22.9Calhoun County: 22.9 %Calhoun County22.9Muskegon County: 22.5 %Muskegon County22.5Missaukee County: 22.4 %Missaukee County22.4Barry County: 22.2 %Barry County22.2Genesee County: 22.2 %Genesee County22.2Newaygo County: 22.1 %Newaygo County22.1Oceana County: 22.1 %Oceana County22.1Clinton County: 22 %Clinton County22Hillsdale County: 21.8 %Hillsdale County21.8Kalamazoo County: 21.8 %Kalamazoo County21.8Saginaw County: 21.5 %Saginaw County21.5Berrien County: 21.3 %Berrien County21.3Ionia County: 21.3 %Ionia County21.3Sanilac County: 21.3 %Sanilac County21.3Midland County: 21.3 %Midland County21.3Montcalm County: 21.1 %Montcalm County21.1Jackson County: 21.1 %Jackson County21.1Cass County: 21 %Cass County21Monroe County: 21 %Monroe County21Eaton County: 21 %Eaton County21Livingston County: 20.8 %Livingston County20.8Ingham County: 20.8 %Ingham County20.8Tuscola County: 20.8 %Tuscola County20.8Lenawee County: 20.7 %Lenawee County20.7Shiawassee County: 20.6 %Shiawassee County20.6Otsego County: 20.4 %Otsego County20.4Macomb County: 20.3 %Macomb County20.3St. Clair County: 20.3 %St. Clair County20.3Lapeer County: 20.3 %Lapeer County20.3Oakland County: 20.2 %Oakland County20.2Kalkaska County: 20 %Kalkaska County20
%. Source: Invokely calculation with data from U.S. Census Bureau. Retrieved 2026-10-12.

Full ranking

RankCounties2021 (%)Change on 2020
1St. Joseph County24.4-0.2 pts
2Branch County23.90 pts
3Allegan County23.6-0.4 pts
4Kent County23.5-0.3 pts
5Ottawa County23.4-0.2 pts
6Wayne County23.3-0.1 pts
7Osceola County23.1-0.3 pts
8Wexford County23-0.2 pts
9Van Buren County22.9-0.1 pts
10Calhoun County22.9-0.1 pts
11Muskegon County22.5-0.2 pts
12Missaukee County22.4-0.2 pts
13Barry County22.2-0.3 pts
14Genesee County22.2-0.3 pts
15Newaygo County22.1-0.4 pts
16Oceana County22.1-0.5 pts
17Clinton County22-0.4 pts
18Hillsdale County21.8-0.3 pts
19Kalamazoo County21.8-0.2 pts
20Saginaw County21.5-0.4 pts
21Berrien County21.3-0.3 pts
22Ionia County21.3-0.4 pts
23Sanilac County21.3+0.1 pts
24Midland County21.3-0.2 pts
25Montcalm County21.1-0.2 pts
26Jackson County21.1-0.2 pts
27Cass County21-0.2 pts
28Monroe County21-0.1 pts
29Eaton County21-0.2 pts
30Livingston County20.8-0.3 pts
31Ingham County20.8+0.8 pts
32Tuscola County20.8-0.3 pts
33Lenawee County20.7-0.3 pts
34Shiawassee County20.6-0.2 pts
35Otsego County20.4-0.3 pts
36Macomb County20.3-0.2 pts
37St. Clair County20.3-0.2 pts
38Lapeer County20.3-0.3 pts
39Oakland County20.2-0.3 pts
40Kalkaska County20-0.3 pts
41Clare County19.9-0.1 pts
42Houghton County19.80 pts
43Mason County19.8-0.2 pts
44Gratiot County19.7-1.6 pts
45Dickinson County19.6-0.1 pts
46Mecosta County19.6-0.3 pts
47Grand Traverse County19.5-0.2 pts
48Bay County19.5-0.3 pts
49Delta County19.4-0.2 pts
50Isabella County19.20 pts
51Chippewa County19+0.3 pts
52Oscoda County18.8+0.1 pts
53Gladwin County18.8-0.1 pts
54Huron County18.7-0.1 pts
55Alpena County18.6+0.1 pts
56Washtenaw County18.2-0.2 pts
57Arenac County18.2-0.1 pts
58Ogemaw County18.1-0.3 pts
59Crawford County18.1-0 pts
60Emmet County18.1-0.2 pts
61Charlevoix County18-0.4 pts
62Marquette County17.9-0.1 pts
63Menominee County17.9-0.3 pts
64Baraga County17.7+0.4 pts
65Schoolcraft County17.4-0 pts
66Luce County17.2+0.9 pts
67Benzie County17.1-0.2 pts
68Iosco County17.1-0 pts
69Antrim County16.9-0.4 pts
70Iron County16.9-0.2 pts
71Cheboygan County16.7-0.4 pts
72Manistee County16.6-0.3 pts
73Gogebic County16.5-0.1 pts
74Mackinac County16.1-0.4 pts
75Leelanau County16-0.2 pts
76Lake County15.7-0.2 pts
77Alger County15.6-0.2 pts
78Montmorency County15.40 pts
79Keweenaw County15.20 pts
80Presque Isle County15.2-0.2 pts
81Roscommon County14.5+0.1 pts
82Alcona County13.2-0.1 pts
83Ontonagon County11.8+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 Michigan 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 Michigan 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/michigan-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 Michigan 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/michigan-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 Michigan 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/michigan-counties?period=2021 (Accessed: 12 October 2026).

BibTeX
@misc{census_counties_in_michigan_by_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 Michigan 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/michigan-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 Michigan 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/michigan-counties?period=2021
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/population-under-18/michigan-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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Rank Counties in Michigan by population under 18 using official data, and cite the source.
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Questions

Which county has the highest population under 18?

St. Joseph County, with 24.4% in 2021, according to the U.S. Census Bureau.

Which county has the lowest population under 18?

Ontonagon County, with 11.8% 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 Michigan: more rankings