Data / Rankings / Population under 18 / Counties in Pennsylvania

Counties in Pennsylvania by population under 18

Lancaster County had the highest population under 18 of 67 counties in 2021, at 22.9%. Forest County had the lowest, at 8.2%. The median was 19.7% and the figure for Pennsylvania was 20.3%. Source: the U.S. Census Bureau.

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Highest22.9Lancaster County
Lowest8.2Forest County
Median19.767 counties
Pennsylvania20.3History

Map of counties, 2021

Adams County: 19.4 %Allegheny County: 18.3 %Armstrong County: 18.7 %Beaver County: 19 %Bedford County: 19.4 %Berks County: 22 %Blair County: 19.8 %Bradford County: 21.8 %Bucks County: 20 %Butler County: 19.3 %Cambria County: 18.8 %Cameron County: 17.4 %Carbon County: 19.3 %Centre County: 14.8 %Chester County: 22.3 %Clarion County: 19.4 %Clearfield County: 18.3 %Clinton County: 20.5 %Columbia County: 17.8 %Crawford County: 20.7 %Cumberland County: 20.3 %Dauphin County: 21.7 %Delaware County: 21.9 %Elk County: 18.4 %Erie County: 20.7 %Fayette County: 18.9 %Forest County: 8.2 %Franklin County: 22.2 %Fulton County: 20.6 %Greene County: 18.6 %Huntingdon County: 18.3 %Indiana County: 18.5 %Jefferson County: 20.7 %Juniata County: 21.9 %Lackawanna County: 19.7 %Lancaster County: 22.9 %Lawrence County: 19.8 %Lebanon County: 22.2 %Lehigh County: 22.2 %Luzerne County: 19.7 %Lycoming County: 20.6 %McKean County: 19.7 %Mercer County: 19.3 %Mifflin County: 22.3 %Monroe County: 20.1 %Montgomery County: 21 %Montour County: 20.5 %Northampton County: 19.1 %Northumberland County: 20.1 %Perry County: 21.5 %Philadelphia County: 20.5 %Pike County: 18.4 %Potter County: 19.8 %Schuylkill County: 19.2 %Snyder County: 21.4 %Somerset County: 18.2 %Sullivan County: 15.3 %Susquehanna County: 19.4 %Tioga County: 19.7 %Union County: 18.4 %Venango County: 19.7 %Warren County: 19.5 %Washington County: 19.2 %Wayne County: 16.7 %Westmoreland County: 18.1 %Wyoming County: 19.1 %York County: 21.8 %
  • Under 18
  • 18 to 19
  • 19 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

Lancaster County: 22.9 %Lancaster County22.9Chester County: 22.3 %Chester County22.3Mifflin County: 22.3 %Mifflin County22.3Lebanon County: 22.2 %Lebanon County22.2Franklin County: 22.2 %Franklin County22.2Lehigh County: 22.2 %Lehigh County22.2Berks County: 22 %Berks County22Delaware County: 21.9 %Delaware County21.9Juniata County: 21.9 %Juniata County21.9Bradford County: 21.8 %Bradford County21.8York County: 21.8 %York County21.8Dauphin County: 21.7 %Dauphin County21.7Perry County: 21.5 %Perry County21.5Snyder County: 21.4 %Snyder County21.4Montgomery County: 21 %Montgomery County21Jefferson County: 20.7 %Jefferson County20.7Erie County: 20.7 %Erie County20.7Crawford County: 20.7 %Crawford County20.7Fulton County: 20.6 %Fulton County20.6Lycoming County: 20.6 %Lycoming County20.6Philadelphia County: 20.5 %Philadelphia County20.5Montour County: 20.5 %Montour County20.5Clinton County: 20.5 %Clinton County20.5Cumberland County: 20.3 %Cumberland County20.3Monroe County: 20.1 %Monroe County20.1Northumberland County: 20.1 %Northumberland County20.1Bucks County: 20 %Bucks County20Blair County: 19.8 %Blair County19.8Lawrence County: 19.8 %Lawrence County19.8Potter County: 19.8 %Potter County19.8Lackawanna County: 19.7 %Lackawanna County19.7Luzerne County: 19.7 %Luzerne County19.7Venango County: 19.7 %Venango County19.7Tioga County: 19.7 %Tioga County19.7McKean County: 19.7 %McKean County19.7Warren County: 19.5 %Warren County19.5Adams County: 19.4 %Adams County19.4Susquehanna County: 19.4 %Susquehanna County19.4Clarion County: 19.4 %Clarion County19.4Bedford County: 19.4 %Bedford County19.4Lancaster County: 22.9 %Lancaster County22.9Chester County: 22.3 %Chester County22.3Mifflin County: 22.3 %Mifflin County22.3Lebanon County: 22.2 %Lebanon County22.2Franklin County: 22.2 %Franklin County22.2Lehigh County: 22.2 %Lehigh County22.2Berks County: 22 %Berks County22Delaware County: 21.9 %Delaware County21.9Juniata County: 21.9 %Juniata County21.9Bradford County: 21.8 %Bradford County21.8York County: 21.8 %York County21.8Dauphin County: 21.7 %Dauphin County21.7Perry County: 21.5 %Perry County21.5Snyder County: 21.4 %Snyder County21.4Montgomery County: 21 %Montgomery County21Jefferson County: 20.7 %Jefferson County20.7Erie County: 20.7 %Erie County20.7Crawford County: 20.7 %Crawford County20.7Fulton County: 20.6 %Fulton County20.6Lycoming County: 20.6 %Lycoming County20.6Philadelphia County: 20.5 %Philadelphia County20.5Montour County: 20.5 %Montour County20.5Clinton County: 20.5 %Clinton County20.5Cumberland County: 20.3 %Cumberland County20.3Monroe County: 20.1 %Monroe County20.1Northumberland County: 20.1 %Northumberland County20.1Bucks County: 20 %Bucks County20Blair County: 19.8 %Blair County19.8Lawrence County: 19.8 %Lawrence County19.8Potter County: 19.8 %Potter County19.8Lackawanna County: 19.7 %Lackawanna County19.7Luzerne County: 19.7 %Luzerne County19.7Venango County: 19.7 %Venango County19.7Tioga County: 19.7 %Tioga County19.7McKean County: 19.7 %McKean County19.7Warren County: 19.5 %Warren County19.5Adams County: 19.4 %Adams County19.4Susquehanna County: 19.4 %Susquehanna County19.4Clarion County: 19.4 %Clarion County19.4Bedford County: 19.4 %Bedford County19.4
%. Source: Invokely calculation with data from U.S. Census Bureau. Retrieved 2026-10-12.

Full ranking

RankCounties2021 (%)Change on 2020
1Lancaster County22.9-0.2 pts
2Chester County22.3-0.4 pts
3Mifflin County22.3+0.1 pts
4Lebanon County22.2-0.3 pts
5Franklin County22.2-0.2 pts
6Lehigh County22.2-0.2 pts
7Berks County22-0.2 pts
8Delaware County21.9-0.2 pts
9Juniata County21.9-0.3 pts
10Bradford County21.80 pts
11York County21.8-0.1 pts
12Dauphin County21.7-0.1 pts
13Perry County21.5-0.1 pts
14Snyder County21.4-0.2 pts
15Montgomery County21-0.3 pts
16Jefferson County20.7-0.2 pts
17Erie County20.7-0.3 pts
18Crawford County20.70 pts
19Fulton County20.6-0.1 pts
20Lycoming County20.60 pts
21Philadelphia County20.5-0.3 pts
22Montour County20.5-0.1 pts
23Clinton County20.5-0.5 pts
24Cumberland County20.3-0.2 pts
25Monroe County20.1-0.1 pts
26Northumberland County20.1+0.1 pts
27Bucks County20-0.3 pts
28Blair County19.8-0.1 pts
29Lawrence County19.8-0.1 pts
30Potter County19.8-0 pts
31Lackawanna County19.70 pts
32Luzerne County19.7+0.1 pts
33Venango County19.7-0.1 pts
34Tioga County19.7-0.4 pts
35McKean County19.7-0.3 pts
36Warren County19.5+0.1 pts
37Adams County19.4-0.5 pts
38Susquehanna County19.4-0.1 pts
39Clarion County19.4-0.3 pts
40Bedford County19.4-0.1 pts
41Mercer County19.3-0.1 pts
42Butler County19.3-0.5 pts
43Carbon County19.3+0.1 pts
44Washington County19.2-0.1 pts
45Schuylkill County19.2+0.1 pts
46Wyoming County19.1-0 pts
47Northampton County19.1-0.5 pts
48Beaver County19-0.1 pts
49Fayette County18.9-0 pts
50Cambria County18.80 pts
51Armstrong County18.7-0.1 pts
52Greene County18.6-0.1 pts
53Indiana County18.5-0.2 pts
54Pike County18.4-0.1 pts
55Elk County18.4-0.1 pts
56Union County18.4-0.3 pts
57Clearfield County18.3+0.2 pts
58Huntingdon County18.3-0.1 pts
59Allegheny County18.3-0.2 pts
60Somerset County18.2+0.1 pts
61Westmoreland County18.1-0.1 pts
62Columbia County17.8-0.2 pts
63Cameron County17.4-0.3 pts
64Wayne County16.70 pts
65Sullivan County15.30 pts
66Centre County14.8-0.3 pts
67Forest County8.2+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 Pennsylvania 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 Pennsylvania 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/pennsylvania-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 Pennsylvania 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/pennsylvania-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 Pennsylvania 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/pennsylvania-counties?period=2021 (Accessed: 12 October 2026).

BibTeX
@misc{census_counties_in_pennsylvania_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 Pennsylvania 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/pennsylvania-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 Pennsylvania 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/pennsylvania-counties?period=2021
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/population-under-18/pennsylvania-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?

Lancaster County, with 22.9% in 2021, according to the U.S. Census Bureau.

Which county has the lowest population under 18?

Forest County, with 8.2% 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 Pennsylvania: more rankings