Data / Rankings / Population under 18 / US counties

US counties by population under 18

Todd County had the highest population under 18 of 3135 counties in 2018, at 40.6%. Sumter County had the lowest, at 7.1%. The median was 22.2% and the figure for the United States was 22.4%. Source: the U.S. Census Bureau.

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Highest40.6Todd County
Lowest7.1Sumter County
Median22.23135 counties
United States22.4History

Map of counties, 2018

%, 2018. Hatched areas have no value for this period. 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 County40.6Kusilvak Census Area: 40.3 %Kusilvak Census Area40.3Buffalo County: 39.2 %Buffalo County39.2Oglala Lakota County: 37.8 %Oglala Lakota County37.8Corson County: 36.6 %Corson County36.6Sioux County: 35.8 %Sioux County35.8Morgan County: 35.6 %Morgan County35.6Bethel Census Area: 35.6 %Bethel Census Area35.6Northwest Arctic Borough: 35.3 %Northwest Arctic Borough35.3Ziebach County: 35 %Ziebach County35Thurston County: 34.8 %Thurston County34.8Jefferson County: 34.6 %Jefferson County34.6Juab County: 34.5 %Juab County34.5Gaines County: 34.2 %Gaines County34.2Rolette County: 34.1 %Rolette County34.1Adams County: 34.1 %Adams County34.1Benson County: 33.9 %Benson County33.9Big Horn County: 33.7 %Big Horn County33.7Uintah County: 33.7 %Uintah County33.7Nome Census Area: 33.7 %Nome Census Area33.7Tooele County: 33.6 %Tooele County33.6Utah County: 33.6 %Utah County33.6LaGrange County: 33.4 %LaGrange County33.4Dewey County: 33 %Dewey County33Bennett County: 33 %Bennett County33Davis County: 32.8 %Davis County32.8Duchesne County: 32.8 %Duchesne County32.8Menominee County: 32.5 %Menominee County32.5Mellette County: 32.4 %Mellette County32.4Franklin County: 32.4 %Franklin County32.4Franklin County: 32.1 %Franklin County32.1Box Elder County: 32.1 %Box Elder County32.1Cassia County: 31.7 %Cassia County31.7Wasatch County: 31.6 %Wasatch County31.6Zapata County: 31.5 %Zapata County31.5Holmes County: 31.5 %Holmes County31.5Adams County: 31.5 %Adams County31.5Jackson County: 31.4 %Jackson County31.4Webb County: 31.4 %Webb County31.4Seward County: 31.3 %Seward County31.3Todd County: 40.6 %Todd County40.6Kusilvak Census Area: 40.3 %Kusilvak Census Area40.3Buffalo County: 39.2 %Buffalo County39.2Oglala Lakota County: 37.8 %Oglala Lakota County37.8Corson County: 36.6 %Corson County36.6Sioux County: 35.8 %Sioux County35.8Morgan County: 35.6 %Morgan County35.6Bethel Census Area: 35.6 %Bethel Census Area35.6Northwest Arctic Borough: 35.3 %Northwest Arctic Borough35.3Ziebach County: 35 %Ziebach County35Thurston County: 34.8 %Thurston County34.8Jefferson County: 34.6 %Jefferson County34.6Juab County: 34.5 %Juab County34.5Gaines County: 34.2 %Gaines County34.2Rolette County: 34.1 %Rolette County34.1Adams County: 34.1 %Adams County34.1Benson County: 33.9 %Benson County33.9Big Horn County: 33.7 %Big Horn County33.7Uintah County: 33.7 %Uintah County33.7Nome Census Area: 33.7 %Nome Census Area33.7Tooele County: 33.6 %Tooele County33.6Utah County: 33.6 %Utah County33.6LaGrange County: 33.4 %LaGrange County33.4Dewey County: 33 %Dewey County33Bennett County: 33 %Bennett County33Davis County: 32.8 %Davis County32.8Duchesne County: 32.8 %Duchesne County32.8Menominee County: 32.5 %Menominee County32.5Mellette County: 32.4 %Mellette County32.4Franklin County: 32.4 %Franklin County32.4Franklin County: 32.1 %Franklin County32.1Box Elder County: 32.1 %Box Elder County32.1Cassia County: 31.7 %Cassia County31.7Wasatch County: 31.6 %Wasatch County31.6Zapata County: 31.5 %Zapata County31.5Holmes County: 31.5 %Holmes County31.5Adams County: 31.5 %Adams County31.5Jackson County: 31.4 %Jackson County31.4Webb County: 31.4 %Webb County31.4Seward County: 31.3 %Seward County31.3
%. 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
2Kusilvak Census Area40.3-0.2 pts
3Buffalo County39.2+0.1 pts
4Oglala Lakota County37.8-0.3 pts
5Corson County36.6+0.4 pts
6Sioux County35.8-1.1 pts
7Morgan County35.6-0.2 pts
8Bethel Census Area35.6-0.2 pts
9Northwest Arctic Borough35.3-0.3 pts
10Ziebach County35-0.7 pts
11Thurston County34.8-0.1 pts
12Jefferson County34.6-0.1 pts
13Juab County34.5-0.5 pts
14Gaines County34.2-0.3 pts
15Rolette County34.1+0.1 pts
16Adams County34.1-0.2 pts
17Benson County33.9+0.2 pts
18Big Horn County33.7-0.4 pts
19Uintah County33.7-0.1 pts
20Nome Census Area33.7-0.3 pts
21Tooele County33.6-0.5 pts
22Utah County33.6-0.4 pts
23LaGrange County33.4-0.3 pts
24Dewey County33+0.4 pts
25Bennett County33+0.1 pts
26Davis County32.8-0.4 pts
27Duchesne County32.8-0.6 pts
28Menominee County32.5-0.1 pts
29Mellette County32.4+0.5 pts
30Franklin County32.4-0.7 pts
31Franklin County32.1-0.4 pts
32Box Elder County32.1-0.3 pts
33Cassia County31.7-0.1 pts
34Wasatch County31.6-0.5 pts
35Zapata County31.5-0.5 pts
36Holmes County31.5-0.5 pts
37Adams County31.5+0.1 pts
38Jackson County31.4-0.4 pts
39Webb County31.4-0.7 pts
40Seward County31.3+0.1 pts
41Hamlin County31.3-0.1 pts
42Dillingham Census Area31.3+0.1 pts
43Roosevelt County31.3-0.5 pts
44Bingham County31.3-0.2 pts
45Hidalgo County31.2-0.6 pts
46Glacier County31.2-0 pts
47Millard County31.1-0.3 pts
48Bailey County31.1-0.3 pts
49Power County31+0.1 pts
50Starr County30.9-0.4 pts
51Jerome County30.9-0.1 pts
52Ford County30.9-0.3 pts
53Grant County30.8-0.7 pts
54Ochiltree County30.8-0.2 pts
55Bonneville County30.7-0.3 pts
56Sevier County30.7-0.1 pts
57Beaver County30.7-0.3 pts
58Deaf Smith County30.7-0.4 pts
59Tulare County30.5-0.3 pts
60Andrews County30.4+0.2 pts
61Hanson County30.3-0.5 pts
62Scotland County30.3+0.3 pts
63Moore County30.2-0.5 pts
64Long County30.2-0 pts
65Rich County30.1+0.4 pts
66Colfax County30.1-0 pts
67Maverick County30-0.5 pts
68Haskell County29.9-0.5 pts
69Caribou County29.9+0.3 pts
70Lyman County29.9-0.2 pts
71Finney County29.9-0.3 pts
72Cache County29.8-0.3 pts
73Mahnomen County29.8-0.6 pts
74Oldham County29.8-0.3 pts
75Lincoln County29.7-0.9 pts
76Dallam County29.6-0.5 pts
77San Juan County29.6-0.6 pts
78Hamilton County29.6-1 pts
79Sherman County29.5+0.1 pts
80Emery County29.5-0.3 pts
81Cameron County29.5-0.6 pts
82Parmer County29.4-0.2 pts
83Blaine County29.4-0.1 pts
84Davis County29.4+0.3 pts
85Geary County29.4-0.5 pts
86Stevens County29.4-0.1 pts
87Pottawatomie County29.3+0.2 pts
88Iron County29.3+0.1 pts
89Merced County29.2-0.3 pts
90Kendall County29.2-0.3 pts
91Oneida County29.1+0.3 pts
92Lea County29.1-0.3 pts
93Daviess County29.1-0 pts
93Yoakum County29.1-0.7 pts
95Lyon County29.1+0.1 pts
95Uinta County29.1-0.4 pts
97Hemphill County29.1-2.1 pts
98Zavala County29.1-0.1 pts
99Charles Mix County290 pts
100Crane County29-0.5 pts
101Texas County29+0.1 pts
102Clark County29-0.1 pts
103Grant County29-0.4 pts
104Canyon County28.9-0.5 pts
105Tunica County28.8+0.3 pts
106Martin County28.8-0.1 pts
107McKenzie County28.8+0.4 pts
108Hansford County28.8-0.4 pts
109Yakima County28.7-0.3 pts
110King County28.7-1.1 pts
111Bryan County28.7-0 pts
112Lincoln County28.7-0.3 pts
113Loudoun County28.7-0.3 pts
114Greenlee County28.7-0.1 pts
115Rockland County28.7+0.3 pts
116Winkler County28.7-0.2 pts
117Minidoka County28.6-0.1 pts
118Dakota County28.6-0.1 pts
118Kern County28.6-0.2 pts
120Gray County28.6-0.2 pts
121Forsyth County28.5-0.4 pts
122Fremont County28.5-0.2 pts
123Weber County28.5-0.3 pts
124Stanton County28.5-0.2 pts
125Wright County28.4-0.2 pts
126Castro County28.4-0.3 pts
127Reagan County28.4-1 pts
128McKinley County28.4-0.5 pts
129Graham County28.4-0.1 pts
130Elko County28.4+0.2 pts
131Loving County28.3-6.2 pts
132Kearny County28.3+0.1 pts
133Sanpete County28.3-0 pts
134Hoke County28.3-0.2 pts
135Dallas County28.3-0.3 pts
136Kaufman County28.2+0.1 pts
137Sevier County28.2-0.2 pts
138Colusa County28.2-0.3 pts
139Cochran County28.2-0.4 pts
140Gooding County28.1-0.3 pts
141Lake and Peninsula Borough28.1-0.3 pts
142Williamson County28.1-0.2 pts
143Roberts County28.1+0.5 pts
144Campbell County28-0.2 pts
145Fresno County28-0.2 pts
146Jim Hogg County27.9-0.4 pts
147Dawson County27.9-0.1 pts
148Upton County27.9-0.3 pts
149Ector County27.9-0 pts
150Sioux County27.9-0 pts
151Sarpy County27.8-0.2 pts
152Fort Bend County27.8-0.2 pts
152Lynn County27.8+0.2 pts
154Titus County27.8-0.3 pts
155Chambers County27.8-0.1 pts
156Oconee County27.8+0.1 pts
157Scott County27.7-0.5 pts
158Hamilton County27.7-0.3 pts
159Morrow County27.7+0.3 pts
159Twin Falls County27.7-0.4 pts
161Dimmit County27.7-0.6 pts
162Union County27.7-0.3 pts
163Owyhee County27.7-0.3 pts
164Floyd County27.6+0.2 pts
165Carver County27.6-0.2 pts
166Madera County27.6-0.1 pts
167St. Bernard Parish27.60 pts
168Elkhart County27.6-0.2 pts
169Mountrail County27.6+0.3 pts
170Midland County27.6+0.2 pts
171Terry County27.5-0.3 pts
172Arthur County27.5+0.9 pts
173Nobles County27.5+0.5 pts
174Lamb County27.5-0.1 pts
175Wyandotte County27.4-0.2 pts
176Ascension Parish27.4-0.2 pts
177Neshoba County27.4-0.6 pts
177Rockwall County27.4-0.2 pts
179Rosebud County27.4-0.5 pts
180Manassas Park city27.4-0.7 pts
181Kingfisher County27.3+0.2 pts
182Bear Lake County27.3-0.4 pts
183Matanuska-Susitna Borough27.3-0.4 pts
184Delaware County27.2-0.4 pts
185Prince William County27.2-0.3 pts
185Schley County27.2-0.2 pts
187Yuba County27.2+0.1 pts
188Jim Wells County27.1-0.4 pts
189Washington County27.1-0.6 pts
190Scott County27.1+0.3 pts
191Webster County27.1-0.1 pts
192Hall County27.1+0.1 pts
193Conejos County27.1-0.4 pts
194Montgomery County27.1-0.1 pts
195Canadian County27.1+0.2 pts
196Benton County27.1-0.2 pts
196Salt Lake County27.1-0.5 pts
198San Juan County27-0.5 pts
199Liberty County27+0.2 pts
200Val Verde County27-0.4 pts
201Sweetwater County27-0.3 pts
202Todd County27+0.3 pts
203Beadle County270 pts
203Wichita County27+0.4 pts
205Imperial County26.9-0.3 pts
206Bell County26.9-0.2 pts
207Scott County26.9+0.2 pts
208Atascosa County26.9-0.1 pts
209Jeff Davis County26.9-0.4 pts
210Effingham County26.90 pts
211Ellis County26.9-0.2 pts
212Ward County26.90 pts
213Payette County26.9-0.2 pts
214Fallon County26.9-0.3 pts
215Harnett County26.9-0.3 pts
216San Joaquin County26.9-0.3 pts
217Paulding County26.9-0.4 pts
218Kings County26.8-0.2 pts
219Curry County26.8-0.2 pts
220Oldham County26.8+0.2 pts
221Douglas County26.8-0.7 pts
222Stafford County26.8-0.1 pts
223Boone County26.7-0.2 pts
224Weld County26.7-0.2 pts
225Clayton County26.7-0.3 pts
226Sherburne County26.7-0.1 pts
227Logan County26.7-1.1 pts
228Chaves County26.7-0.2 pts
229Navajo County26.7-0.3 pts
230Boone County26.6-0.2 pts
231Crawford County26.6+0.2 pts
232Benton County26.6-0.1 pts
233Teton County26.6-0.5 pts
234Crosby County26.6-0.4 pts
235Stanislaus County26.6-0.2 pts
236Collin County26.6-0.3 pts
237Crittenden County26.6-0.2 pts
238Santa Cruz County26.6-0.6 pts
239Adams County26.6-0.4 pts
240Morgan County26.5-0.1 pts
241Gwinnett County26.5-0.4 pts
242Golden Valley County26.5+0.4 pts
243Buchanan County26.5-0.3 pts
244Yuma County26.5+0.6 pts
245Williams County26.5+0.5 pts
246Columbia County26.5-0.1 pts
247Humboldt County26.5-0.2 pts
248Leflore County26.5+0.1 pts
249Montgomery County26.5-0.2 pts
250Bannock County26.4-0.3 pts

Showing the top 250 of 3135. The Excel download has every row.

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. 9 counties with data in other periods have no value for 2018 and are left out rather than filled from another source. 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 (US counties 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, US counties 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/us-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. US counties 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/us-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, US counties 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/us-counties?period=2018 (Accessed: 12 October 2026).

BibTeX
@misc{census_us_counties_by_population_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: US counties 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/us-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: US counties 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/us-counties?period=2018
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/population-under-18/us-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?

Sumter County, with 7.1% 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. 9 counties have no value for 2018 and are not ranked.

Population under 18: other rankings

US counties: more rankings