# Counties in New Hampshire by population under 18, 2025

All 10 values come from U.S. Census Bureau for 2025, so the places are comparable.

- Indicator id: `population_0_17_share`
- Unit: %
- Definition: 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.
- Source: 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: 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.
- Web page: https://invokely.ai/rankings/population-under-18/new-hampshire-counties

| Rank | Place | % |
|---:|---|---:|
| 1 | Hillsborough County | 18.7 |
| 2 | Rockingham County | 17.6 |
| 3 | Merrimack County | 17.5 |
| 4 | Cheshire County | 17.3 |
| 5 | Sullivan County | 16.8 |
| 6 | Strafford County | 16.5 |
| 7 | Belknap County | 15.8 |
| 8 | Coos County | 15.4 |
| 9 | Grafton County | 14.6 |
| 10 | Carroll County | 13.9 |