Data / Rankings / Population under 18 / Counties in Pennsylvania

Counties in Pennsylvania by population under 18, 2025

Lancaster County had the highest population under 18 of 67 counties in 2025, at 22.3%. Forest County had the lowest, at 7.8%. The median was 19.3% and the figure for Pennsylvania was 19.7%. Source: the U.S. Census Bureau.

Highest22.3Lancaster County
Lowest7.8Forest County
Median19.367 counties
Pennsylvania19.7History

Top 40 counties, 2025

Lancaster County: 22.3 %Lancaster County22.3Mifflin County: 22.2 %Mifflin County22.2Juniata County: 22 %Juniata County22Lebanon County: 21.6 %Lebanon County21.6Delaware County: 21.6 %Delaware County21.6Franklin County: 21.5 %Franklin County21.5Bradford County: 21.5 %Bradford County21.5Lehigh County: 21.3 %Lehigh County21.3Berks County: 21.3 %Berks County21.3York County: 21.2 %York County21.2Dauphin County: 21.1 %Dauphin County21.1Chester County: 21.1 %Chester County21.1Perry County: 21.1 %Perry County21.1Snyder County: 20.5 %Snyder County20.5Jefferson County: 20.5 %Jefferson County20.5Crawford County: 20.3 %Crawford County20.3Montgomery County: 20.2 %Montgomery County20.2Cumberland County: 20.1 %Cumberland County20.1Luzerne County: 20 %Luzerne County20Clinton County: 19.9 %Clinton County19.9Fulton County: 19.9 %Fulton County19.9Philadelphia County: 19.9 %Philadelphia County19.9Lycoming County: 19.8 %Lycoming County19.8Northumberland County: 19.7 %Northumberland County19.7Lackawanna County: 19.6 %Lackawanna County19.6Montour County: 19.6 %Montour County19.6Erie County: 19.6 %Erie County19.6Clarion County: 19.6 %Clarion County19.6Susquehanna County: 19.5 %Susquehanna County19.5Bedford County: 19.4 %Bedford County19.4Tioga County: 19.3 %Tioga County19.3Schuylkill County: 19.3 %Schuylkill County19.3Bucks County: 19.3 %Bucks County19.3Blair County: 19.3 %Blair County19.3Warren County: 19.3 %Warren County19.3Lawrence County: 19.3 %Lawrence County19.3Venango County: 19.2 %Venango County19.2Potter County: 18.9 %Potter County18.9Mercer County: 18.9 %Mercer County18.9Washington County: 18.8 %Washington County18.8
%. Source: Invokely calculation with data from U.S. Census Bureau. Retrieved 2026-10-12.

Full ranking

RankCounties2025 (%)Change on 2024
1Lancaster County22.3-0.3 pts
2Mifflin County22.2-0 pts
3Juniata County22-0.1 pts
4Lebanon County21.6-0.2 pts
5Delaware County21.6-0.1 pts
6Franklin County21.5-0.2 pts
7Bradford County21.5-0.2 pts
8Lehigh County21.3-0.2 pts
9Berks County21.3-0.2 pts
10York County21.2-0.2 pts
11Dauphin County21.1-0.2 pts
12Chester County21.1-0.3 pts
13Perry County21.1-0.2 pts
14Snyder County20.5-0.4 pts
15Jefferson County20.5-0 pts
16Crawford County20.3-0.1 pts
17Montgomery County20.2-0.2 pts
18Cumberland County20.1-0.2 pts
19Luzerne County200 pts
20Clinton County19.9-0.1 pts
21Fulton County19.9-0.3 pts
22Philadelphia County19.9-0.2 pts
23Lycoming County19.8-0.2 pts
24Northumberland County19.7-0.1 pts
25Lackawanna County19.6-0 pts
26Montour County19.6-0.2 pts
27Erie County19.6-0.3 pts
28Clarion County19.6-0 pts
29Susquehanna County19.5-0 pts
30Bedford County19.4-0.1 pts
31Tioga County19.3-0.2 pts
32Schuylkill County19.3-0 pts
33Bucks County19.3-0.2 pts
34Blair County19.3-0.2 pts
35Warren County19.3-0.2 pts
36Lawrence County19.3-0.2 pts
37Venango County19.2-0.3 pts
38Potter County18.9-0.3 pts
39Mercer County18.9-0.1 pts
40Washington County18.8-0.2 pts
41Monroe County18.7-0.4 pts
42McKean County18.7-0.3 pts
43Beaver County18.4-0.1 pts
44Fayette County18.4-0.4 pts
45Cambria County18.4-0.2 pts
46Wyoming County18.4-0.2 pts
47Adams County18.4-0.4 pts
48Butler County18.4-0.2 pts
49Carbon County18.3-0.3 pts
50Armstrong County18.2-0.2 pts
51Northampton County18.2-0.3 pts
52Indiana County18.1-0.2 pts
53Elk County18.1-0.1 pts
54Huntingdon County17.9-0.1 pts
55Allegheny County17.8-0.1 pts
56Greene County17.8-0.4 pts
57Somerset County17.7-0.2 pts
58Westmoreland County17.6-0.2 pts
59Clearfield County17.5-0.2 pts
60Pike County17.3-0.3 pts
61Columbia County17.3-0.1 pts
61Union County17.3-0.1 pts
63Cameron County16.6-0.6 pts
64Wayne County16.2-0.3 pts
65Centre County14.3-0.1 pts
66Sullivan County13.2-0.6 pts
67Forest County7.8-0.4 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, 2025) [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, 2025. 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. 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, 2025. 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.

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, 2025 [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 (Accessed: 12 October 2026).

BibTeX
@misc{census_counties_in_pennsylvania_by_2025,
  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, 2025}},
  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. 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, 2025
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
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/population-under-18/pennsylvania-counties.
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 22.3% in 2025, according to the U.S. Census Bureau.

Which county has the lowest population under 18?

Forest County, with 7.8% in 2025.

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