There were 1,374 more people living in Hillsborough County in 2021 compared to 2020, according to population estimates from the US Census Bureau.
This is less than a one percent rise in Hillsborough County’s population, from 422,705 in 2020 to 424,079 in 2021.
Hillsborough County had the largest population in New Hampshire in 2021.
The US Census Bureau found more than 73 percent of counties in the US saw a natural decrease in population in 2021. This is up from a 55.5 percent increase in 2020.
The Midwest suffered the most sustained population decreases, with many counties along the US East Coast and through the Rocky Mountains seeing increases.
The US population continues to grow, though at a slower rate than before.
New Hampshire Counties By Population Change from 2020 to 2021
| County | 2020 Estimated Population | 2021 Estimated Population | % Change in Population From Year to Year |
|---|---|---|---|
| Carroll County | 50,212 | 51,500 | 2.6% |
| Grafton County | 91,123 | 92,201 | 1.2% |
| Sullivan County | 43,033 | 43,533 | 1.2% |
| Belknap County | 63,743 | 64,460 | 1.1% |
| Cheshire County | 76,501 | 77,329 | 1.1% |
| Strafford County | 131,006 | 132,416 | 1.1% |
| Merrimack County | 153,922 | 155,238 | 0.9% |
| Rockingham County | 314,430 | 316,947 | 0.8% |
| Coos County | 31,173 | 31,289 | 0.4% |
| Hillsborough County | 422,705 | 424,079 | 0.3% |
