New Hampshire Counties by Population (2026)
2026 Pop.
50K
100K
150K
200K
250K
300K
350K
400K
Top 5 Most Populous Counties
436,388
326,153
158,609
135,755
93,457
10 Counties
| County | 2026 Pop. ↓ | Area (mi²) | Density | Change (2020) |
|---|---|---|---|---|
| Hillsborough County | 436,388 | 877 | 498 | 3.19% |
| Rockingham County | 326,153 | 695 | 469 | 3.66% |
| Merrimack County | 158,609 | 933 | 170 | 2.95% |
| Strafford County | 135,755 | 367 | 370 | 3.56% |
| Grafton County | 93,457 | 1.7K | 55 | 2.48% |
| Cheshire County | 78,370 | 707 | 111 | 2.39% |
| Belknap County | 65,125 | 402 | 162 | 2.11% |
| Carroll County | 53,002 | 932 | 57 | 5.47% |
| Sullivan County | 43,998 | 538 | 82 | 2.15% |
| Coos County | 31,309 | 1.8K | 17 | 0.24% |
Overview of New Hampshire Counties
There are 10 counties in New Hampshire.
Hillsborough County is the largest county in the state, with a population of 436,388. The most recent census shows that its population has increased by 0.03% since the previous census.
A number of other New Hampshire counties also boast relatively large populations for their state, though not able to match the density of Hillsborough County:
- Rockingham County : 326,153
- Merrimack County : 158,609
New Hampshire Counties with the Fewest Residents
The smallest county in New Hampshire is Coos County , with a population of just 31,309. This total represents a increase of 0.0% since the last census count was performed.
Other small counties include:
- Sullivan County : 43,998
- Carroll County : 53,002
- Belknap County : 65,125
New Hampshire Counties with Rapid Growth
Carroll County , with its current population of 53,002, has shown the largest population growth, with an increase of 0.1% since the last census.
Sources
- US Census State Population Estimates - Most recent state estimates from the Census Bureau's Population Estimates Program
- US Census County Population Estimates - Most recent county estimates from the Census Bureau's Population Estimates Program
- American Community Survey (2009 - 2013)
- Census QuickFacts
- Historical Populations of States and Counties (1790 - 1990)