RANKING · 2025 ESTIMATES · 10 SHOWN OF 10

Fastest growing, New Hampshire counties

New Hampshire counties ranked by population growth from the 2020 census to 2025. This list covers the 10 counties in New Hampshire that qualify, ranked against each other statewide. The median across all 10 is +2.5%. Biggest climber in the top 100 since 2020: Carroll County, NH, up 5 places to #1.

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SAME RANKING BYCities States Metros

RELATEDLargest by population Fastest shrinking Most population gained Most population lost Most densely populated Most sparsely populated

YEAR2000 2010 2020 2025

RANKPLACESTATEPOPPOPULATION GROWTHVS 2000

01▲5Carroll County, NHNH52,784+5.3%−18.0 pts

02Strafford County, NHNH135,043+3.2%−4.5 pts

03▼2Rockingham County, NHNH324,077+3.2%−9.7 pts

04▲1Merrimack County, NHNH158,078+2.8%−10.7 pts

05▼1Hillsborough County, NHNH433,415+2.5%−10.8 pts

06▲2Cheshire County, NHNH78,269+2.4%−2.9 pts

07Grafton County, NHNH93,225+2.3%−6.8 pts

08▼5Belknap County, NHNH65,147+2.3%−12.2 pts

09Sullivan County, NHNH43,961+2.1%−2.7 pts

10Coos County, NHNH31,343+0.2%+5.2 pts

SHOWING 1–10 OF 10

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UPDATED 2026-09-11 · DATA: US CENSUS BUREAU POPULATION ESTIMATES