Counties in Pennsylvania by population under 18

Lancaster County had the highest population under 18 of 67 counties in 2017, at 23.6%. Forest County had the lowest, at 8.9%. The median was 20.1% and the figure for Pennsylvania was 20.7%. Source: the U.S. Census Bureau.

Highest23.6Lancaster County
Lowest8.9Forest County
Median20.167 counties
Pennsylvania20.7History

Top 40 counties, 2017

Lancaster County: 23.6 %Lancaster County23.6Chester County: 23.2 %Chester County23.2Franklin County: 22.8 %Franklin County22.8Berks County: 22.6 %Berks County22.6Lebanon County: 22.6 %Lebanon County22.6Juniata County: 22.4 %Juniata County22.4Lehigh County: 22.4 %Lehigh County22.4York County: 22.3 %York County22.3Delaware County: 22.1 %Delaware County22.1Mifflin County: 22.1 %Mifflin County22.1Dauphin County: 22 %Dauphin County22Bradford County: 22 %Bradford County22Perry County: 21.9 %Perry County21.9Snyder County: 21.7 %Snyder County21.7Montgomery County: 21.6 %Montgomery County21.6Erie County: 21.5 %Erie County21.5Crawford County: 21.1 %Crawford County21.1Philadelphia County: 21.1 %Philadelphia County21.1Jefferson County: 20.9 %Jefferson County20.9Clinton County: 20.9 %Clinton County20.9Bucks County: 20.8 %Bucks County20.8Potter County: 20.6 %Potter County20.6Montour County: 20.6 %Montour County20.6Adams County: 20.6 %Adams County20.6Lycoming County: 20.5 %Lycoming County20.5Fulton County: 20.5 %Fulton County20.5Monroe County: 20.4 %Monroe County20.4Butler County: 20.4 %Butler County20.4Venango County: 20.4 %Venango County20.4Cumberland County: 20.3 %Cumberland County20.3Tioga County: 20.2 %Tioga County20.2Blair County: 20.2 %Blair County20.2McKean County: 20.2 %McKean County20.2Northumberland County: 20.1 %Northumberland County20.1Mercer County: 20 %Mercer County20Northampton County: 20 %Northampton County20Lackawanna County: 19.9 %Lackawanna County19.9Bedford County: 19.8 %Bedford County19.8Lawrence County: 19.8 %Lawrence County19.8Wyoming County: 19.7 %Wyoming County19.7
%. Source: Invokely calculation with data from U.S. Census Bureau. Retrieved 2026-10-12.

Full ranking

RankCounties2017 (%)Change on 2016
1Lancaster County23.6-0.1 pts
2Chester County23.2-0.2 pts
3Franklin County22.8-0.1 pts
4Berks County22.6-0.1 pts
5Lebanon County22.6-0.1 pts
6Juniata County22.4-0.1 pts
7Lehigh County22.4-0 pts
8York County22.3-0 pts
9Delaware County22.1-0.1 pts
10Mifflin County22.1-0.1 pts
11Dauphin County220 pts
12Bradford County22-0 pts
13Perry County21.9-0.1 pts
14Snyder County21.7-0 pts
15Montgomery County21.6-0.1 pts
16Erie County21.5-0.2 pts
17Crawford County21.1-0.1 pts
18Philadelphia County21.1-0.2 pts
19Jefferson County20.9-0 pts
20Clinton County20.9-0.1 pts
21Bucks County20.8-0.2 pts
22Potter County20.6-0.4 pts
23Montour County20.6+0.2 pts
24Adams County20.6-0.2 pts
25Lycoming County20.5-0.1 pts
26Fulton County20.5-0.2 pts
27Monroe County20.4-0.1 pts
28Butler County20.4-0.2 pts
29Venango County20.4-0.2 pts
30Cumberland County20.3-0 pts
31Tioga County20.20 pts
32Blair County20.2-0.2 pts
33McKean County20.2+0.1 pts
34Northumberland County20.1-0 pts
35Mercer County20-0 pts
36Northampton County20-0.2 pts
37Lackawanna County19.9+0.1 pts
38Bedford County19.8-0.3 pts
39Lawrence County19.8-0.2 pts
40Wyoming County19.7-0.2 pts
41Carbon County19.5-0.1 pts
42Warren County19.4-0.1 pts
43Susquehanna County19.4-0.1 pts
44Washington County19.3-0.1 pts
45Luzerne County19.30 pts
46Pike County19.3-0.1 pts
47Beaver County19.3-0.1 pts
48Schuylkill County19.3-0 pts
49Elk County19.3-0.1 pts
50Clarion County19.2-0.2 pts
51Cambria County19.2-0 pts
52Armstrong County19.2-0.1 pts
53Greene County19.1-0 pts
54Fayette County19-0.2 pts
55Indiana County18.70 pts
56Allegheny County18.7-0.1 pts
57Union County18.6+0.2 pts
58Huntingdon County18.6-0.2 pts
59Westmoreland County18.6-0.1 pts
60Clearfield County18.5-0.1 pts
61Columbia County18.20 pts
62Somerset County18.2-0 pts
63Cameron County17.7+0.6 pts
64Wayne County17.2-0.1 pts
65Sullivan County16.4+0.1 pts
66Centre County15.4-0.1 pts
67Forest County8.9-0.2 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 Pennsylvania by population under 18, 2017) [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, 2017. 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=2017. 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, 2017. 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=2017.

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, 2017 [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=2017 (Accessed: 12 October 2026).

BibTeX
@misc{census_counties_in_pennsylvania_by_2017,
  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, 2017}},
  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=2017. 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, 2017
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=2017
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/population-under-18/pennsylvania-counties?period=2017.
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 23.6% in 2017, according to the U.S. Census Bureau.

Which county has the lowest population under 18?

Forest County, with 8.9% in 2017.

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