Data / Rankings / Population / Counties in New Hampshire

Counties in New Hampshire by population

Hillsborough County had the highest population of 10 counties in 2020, at 422,902. Coos County had the lowest, at 31,235. The median was 83,867 and the figure for New Hampshire was 1.38 million. Source: the U.S. Census Bureau.

Highest422,902Hillsborough County
Lowest31,235Coos County
Median83,86710 counties
New Hampshire1,378,752History

All counties, 2020

CSVChart (SVG)

Hillsborough CountyHillsborough County: 422,902 persons422,902Rockingham CountyRockingham County: 314,633 persons314,633Merrimack CountyMerrimack County: 154,061 persons154,061Strafford CountyStrafford County: 131,084 persons131,084Grafton CountyGrafton County: 91,193 persons91,193Cheshire CountyCheshire County: 76,541 persons76,541Belknap CountyBelknap County: 63,779 persons63,779Carroll CountyCarroll County: 50,251 persons50,251Sullivan CountySullivan County: 43,073 persons43,073Coos CountyCoos County: 31,235 persons31,235
persons. Source: U.S. Census Bureau. Retrieved 2026-10-08.

Full ranking

RankCounties2020
persons
1Hillsborough County422,902
2Rockingham County314,633
3Merrimack County154,061
4Strafford County131,084
5Grafton County91,193
6Cheshire County76,541
7Belknap County63,779
8Carroll County50,251
9Sullivan County43,073
10Coos County31,235

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 422,902 in 2020, according to the U.S. Census Bureau.

Which county has the lowest population?

Coos County, with 31,235 in 2020.

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