RANKING · 2020 CENSUS · 10 SHOWN OF 10

Most population gained, New Hampshire counties · 2020

New Hampshire counties that added the most residents from the 2010 census to 2020, by raw count of people rather than percentage. This list covers the 10 counties in New Hampshire that qualify, ranked against each other statewide.

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SAME RANKING BYCities States Metros

YEAR2000 2010 2020 2025

RANKPLACESTATEPOPPOPULATION CHANGEVS 2000

01Hillsborough County, NHNH433,415+22,216−50%

02Rockingham County, NHNH324,077+18,953−40%

03Strafford County, NHNH135,043+7,746−3%

04Merrimack County, NHNH158,078+7,363−55%

05Belknap County, NHNH65,147+3,617−49%

06Carroll County, NHNH52,784+2,289−72%

07Grafton County, NHNH93,225+2,000−71%

08Cheshire County, NHNH78,269-659−118%

09Sullivan County, NHNH43,961-679−136%

10Coos County, NHNH31,343-1,787+4%

SHOWING 1–10 OF 10

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UPDATED 2026-07-15 · DATA: US CENSUS BUREAU DECENNIAL CENSUS