| County Name | Population | State | Rank |
|---|---|---|---|
| Hillsborough County | 400,721 | New Hampshire | 1 |
| Rockingham County | 295,223 | New Hampshire | 2 |
| Merrimack County | 146,445 | New Hampshire | 3 |
| Strafford County | 123,143 | New Hampshire | 4 |
| Grafton County | 89,118 | New Hampshire | 5 |
| Cheshire County | 77,117 | New Hampshire | 6 |
| Belknap County | 60,088 | New Hampshire | 7 |
| Carroll County | 47,818 | New Hampshire | 8 |
| Sullivan County | 43,742 | New Hampshire | 9 |
| Coos County | 33,055 | New Hampshire | 10 |