Data / Rankings / Population / Counties in New Hampshire

Counties in New Hampshire by population, 2025

Hillsborough County had the highest population of 10 counties in 2025, at 433,415. Coos County had the lowest, at 31,343. The median was 85,747 and the figure for New Hampshire was 1.42 million. Source: the U.S. Census Bureau.

Highest433,415Hillsborough County
Lowest31,343Coos County
Median85,74710 counties
New Hampshire1,415,342History

All counties, 2025

CSVChart (SVG)

Hillsborough CountyHillsborough County: 433,415 persons433,415Rockingham CountyRockingham County: 324,077 persons324,077Merrimack CountyMerrimack County: 158,078 persons158,078Strafford CountyStrafford County: 135,043 persons135,043Grafton CountyGrafton County: 93,225 persons93,225Cheshire CountyCheshire County: 78,269 persons78,269Belknap CountyBelknap County: 65,147 persons65,147Carroll CountyCarroll County: 52,784 persons52,784Sullivan CountySullivan County: 43,961 persons43,961Coos CountyCoos County: 31,343 persons31,343
persons. Source: U.S. Census Bureau. Retrieved 2026-10-08.

Full ranking

RankCounties2025
persons		Change on 2024
1Hillsborough County433,415+0.7%
2Rockingham County324,077+0.6%
3Merrimack County158,078+0.3%
4Strafford County135,043+0.5%
5Grafton County93,225+0.2%
6Cheshire County78,269+0.1%
7Belknap County65,147-0%
8Carroll County52,784+0.4%
9Sullivan County43,961+0.1%
10Coos County31,343-0.1%

Other periods

About this ranking

Resident population. Spain and the EU: 1 January, with Spanish figures from the official municipal register (Padrón). United States: Census Bureau population estimates for 1 July. Other countries and the World: World Bank mid-year estimates, which count all residents regardless of legal status or citizenship.

For Denmark, Statistics Denmark counts the registered resident population on 1 January. Greenland and the Faroe Islands are excluded. The annual series selects the first-quarter reference date from FOLK1A. The World Bank series exists for every country, so use it (through compare) to rank countries on one basis.

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. Annual estimates of the resident population for the United States, states and counties, 1 July (Population Estimates Program). https://www2.census.gov/programs-surveys/popest/datasets/2020-2025/. Retrieved 2026-10-08.

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Rank Counties in New Hampshire by population using official data, and cite the source.
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Questions

Which county has the highest population?

Hillsborough County, with 433,415 in 2025, according to the U.S. Census Bureau.

Which county has the lowest population?

Coos County, with 31,343 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, Annual estimates of the resident population for the United States, states and counties, 1 July (Population Estimates Program). Retrieved 2026-10-08.

Population: other rankings

Counties in New Hampshire: more rankings