Counties in New Hampshire by population under 18, 2025
Hillsborough County had the highest population under 18 of 10 counties in 2025, at 18.7%. Carroll County had the lowest, at 13.9%. The median was 16.6% and the figure for New Hampshire was 17.3%. Source: the U.S. Census Bureau.
Map of counties, 2025
- Under 15
- 15 to 16
- 16 to 17
- 17 to 18
- 18 and over
All counties, 2025
Full ranking
| Rank | Counties | 2025 (%) | Change on 2024 |
|---|---|---|---|
| 1 | Hillsborough County | 18.7 | -0.3 pts |
| 2 | Rockingham County | 17.6 | -0.3 pts |
| 3 | Merrimack County | 17.5 | -0.3 pts |
| 4 | Cheshire County | 17.3 | -0.3 pts |
| 5 | Sullivan County | 16.8 | -0.3 pts |
| 6 | Strafford County | 16.5 | -0.3 pts |
| 7 | Belknap County | 15.8 | -0.4 pts |
| 8 | Coos County | 15.4 | -0 pts |
| 9 | Grafton County | 14.6 | -0.3 pts |
| 10 | Carroll County | 13.9 | -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
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 New Hampshire 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 New Hampshire 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/new-hampshire-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 New Hampshire 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/new-hampshire-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 New Hampshire 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/new-hampshire-counties (Accessed: 12 October 2026).
BibTeX
@misc{census_counties_in_new_hampshire_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 New Hampshire 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/new-hampshire-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 New Hampshire 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/new-hampshire-counties
Y2 - 2026/10/12
N1 - Accessed via Invokely, https://invokely.ai/rankings/population-under-18/new-hampshire-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 -
Use this data in your AI agent
Invokely serves this figure to AI assistants through MCP and to code through a REST API, with the source and citation attached. Ask your assistant:
Rank Counties in New Hampshire by population under 18 using official data, and cite the source.
rank_places {"indicator":"population_0_17_share","level":"province","within":"New Hampshire","limit":10}
GET https://invokely.ai/api/v1/rank?indicator=population_0_17_share&level=province&within=New%20Hampshire&limit=10Questions
Which county has the highest population under 18?
Hillsborough County, with 18.7% in 2025, according to the U.S. Census Bureau.
Which county has the lowest population under 18?
Carroll County, with 13.9% 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.