Data / Rankings / Population / Counties in New Hampshire

Counties in New Hampshire by population

Hillsborough County had the highest population of 10 counties in 2021, at 424,484. Coos County had the lowest, at 31,402. The median was 83,688 and the figure for New Hampshire was 1.39 million. Source: the U.S. Census Bureau.

Highest424,484Hillsborough County
Lowest31,402Coos County
Median83,68810 counties
New Hampshire1,387,907History

All counties, 2021

CSVChart (SVG)

Hillsborough CountyHillsborough County: 424,484 persons424,484Rockingham CountyRockingham County: 318,370 persons318,370Merrimack CountyMerrimack County: 154,660 persons154,660Strafford CountyStrafford County: 131,643 persons131,643Grafton CountyGrafton County: 90,518 persons90,518Cheshire CountyCheshire County: 76,858 persons76,858Belknap CountyBelknap County: 64,612 persons64,612Carroll CountyCarroll County: 51,741 persons51,741Sullivan CountySullivan County: 43,619 persons43,619Coos CountyCoos County: 31,402 persons31,402
persons. Source: U.S. Census Bureau. Retrieved 2026-10-08.

Full ranking

RankCounties2021
persons		Change on 2020
1Hillsborough County424,484+0.4%
2Rockingham County318,370+1.2%
3Merrimack County154,660+0.4%
4Strafford County131,643+0.4%
5Grafton County90,518-0.7%
6Cheshire County76,858+0.4%
7Belknap County64,612+1.3%
8Carroll County51,741+3%
9Sullivan County43,619+1.3%
10Coos County31,402+0.5%

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 424,484 in 2021, according to the U.S. Census Bureau.

Which county has the lowest population?

Coos County, with 31,402 in 2021.

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