Counties in Maryland by population under 18

St. Mary's County had the highest population under 18 of 24 counties in 2015, at 24.8%. Kent County had the lowest, at 16.7%. The median was 22.3% and the figure for Maryland was 22.5%. Source: the U.S. Census Bureau.

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Lowest16.7Kent County
Median22.324 counties
Maryland22.5History

Map of counties, 2015

Allegany County: 17.9 %Anne Arundel County: 22.7 %Baltimore County: 21.6 %Calvert County: 24 %Caroline County: 23.8 %Carroll County: 22.3 %Cecil County: 23.3 %Charles County: 24.5 %Dorchester County: 21.2 %Frederick County: 23.9 %Garrett County: 19.8 %Harford County: 22.9 %Howard County: 24.7 %Kent County: 16.7 %Montgomery County: 23.5 %Prince George's County: 22.4 %Queen Anne's County: 22.2 %St. Mary's County: 24.8 %Somerset County: 17.1 %Talbot County: 18.6 %Washington County: 22.2 %Wicomico County: 22.1 %Worcester County: 17.9 %Baltimore city: 20.7 %
  • Under 19
  • 19 to 22
  • 22 to 23
  • 23 to 24
  • 24 and over
%, 2015. Source: Invokely calculation with data from U.S. Census Bureau. Boundaries: U.S. Census Bureau cartographic boundary files.

All counties, 2015

St. Mary's County: 24.8 %St. Mary's County24.8Howard County: 24.7 %Howard County24.7Charles County: 24.5 %Charles County24.5Calvert County: 24 %Calvert County24Frederick County: 23.9 %Frederick County23.9Caroline County: 23.8 %Caroline County23.8Montgomery County: 23.5 %Montgomery County23.5Cecil County: 23.3 %Cecil County23.3Harford County: 22.9 %Harford County22.9Anne Arundel County: 22.7 %Anne Arundel County22.7Prince George's County: 22.4 %Prince George's County22.4Carroll County: 22.3 %Carroll County22.3Washington County: 22.2 %Washington County22.2Queen Anne's County: 22.2 %Queen Anne's County22.2Wicomico County: 22.1 %Wicomico County22.1Baltimore County: 21.6 %Baltimore County21.6Dorchester County: 21.2 %Dorchester County21.2Baltimore city: 20.7 %Baltimore city20.7Garrett County: 19.8 %Garrett County19.8Talbot County: 18.6 %Talbot County18.6Allegany County: 17.9 %Allegany County17.9Worcester County: 17.9 %Worcester County17.9Somerset County: 17.1 %Somerset County17.1Kent County: 16.7 %Kent County16.7St. Mary's County: 24.8 %St. Mary's County24.8Howard County: 24.7 %Howard County24.7Charles County: 24.5 %Charles County24.5Calvert County: 24 %Calvert County24Frederick County: 23.9 %Frederick County23.9Caroline County: 23.8 %Caroline County23.8Montgomery County: 23.5 %Montgomery County23.5Cecil County: 23.3 %Cecil County23.3Harford County: 22.9 %Harford County22.9Anne Arundel County: 22.7 %Anne Arundel County22.7Prince George's County: 22.4 %Prince George's County22.4Carroll County: 22.3 %Carroll County22.3Washington County: 22.2 %Washington County22.2Queen Anne's County: 22.2 %Queen Anne's County22.2Wicomico County: 22.1 %Wicomico County22.1Baltimore County: 21.6 %Baltimore County21.6Dorchester County: 21.2 %Dorchester County21.2Baltimore city: 20.7 %Baltimore city20.7Garrett County: 19.8 %Garrett County19.8Talbot County: 18.6 %Talbot County18.6Allegany County: 17.9 %Allegany County17.9Worcester County: 17.9 %Worcester County17.9Somerset County: 17.1 %Somerset County17.1Kent County: 16.7 %Kent County16.7
%. Source: Invokely calculation with data from U.S. Census Bureau. Retrieved 2026-10-12.

Full ranking

RankCounties2015 (%)Change on 2014
1St. Mary's County24.8-0.2 pts
2Howard County24.7-0.1 pts
3Charles County24.5-0.3 pts
4Calvert County24-0.4 pts
5Frederick County23.9-0.2 pts
6Caroline County23.8-0.1 pts
7Montgomery County23.5-0.1 pts
8Cecil County23.3-0.3 pts
9Harford County22.9-0.2 pts
10Anne Arundel County22.7-0.1 pts
11Prince George's County22.4-0.1 pts
12Carroll County22.3-0.3 pts
13Washington County22.2-0.1 pts
14Queen Anne's County22.2-0.3 pts
15Wicomico County22.1-0 pts
16Baltimore County21.6-0 pts
17Dorchester County21.2-0 pts
18Baltimore city20.7-0.1 pts
19Garrett County19.8-0.4 pts
20Talbot County18.60 pts
21Allegany County17.90 pts
22Worcester County17.9-0.1 pts
23Somerset County17.10 pts
24Kent County16.7-0.3 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 Maryland by population under 18, 2015) [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 Maryland by population under 18, 2015. 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/maryland-counties?period=2015. 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 Maryland by population under 18, 2015. 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/maryland-counties?period=2015.

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 Maryland by population under 18, 2015 [Dataset]. Available at: https://www.census.gov/programs-surveys/popest/data/data-sets.html, via Invokely: https://invokely.ai/rankings/population-under-18/maryland-counties?period=2015 (Accessed: 12 October 2026).

BibTeX
@misc{census_counties_in_maryland_by_2015,
  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 Maryland by population under 18, 2015}},
  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/maryland-counties?period=2015. 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 Maryland by population under 18, 2015
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/maryland-counties?period=2015
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/population-under-18/maryland-counties?period=2015.
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 Maryland 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. Mary's County, with 24.8% in 2015, according to the U.S. Census Bureau.

Which county has the lowest population under 18?

Kent County, with 16.7% in 2015.

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 Maryland: more rankings