| City | County | 2026 Pop. ↓ |
|---|---|---|
| Portsmouth | Rockingham County | 23,164 |
| Pelham | Hillsborough County | 14,975 |
| Plaistow | Rockingham County | 7,850 |
| Pembroke | Merrimack County | 7,634 |
| Plymouth | Grafton County | 6,754 |
| Peterborough | Hillsborough County | 6,542 |
| Pittsfield | Merrimack County | 4,159 |
| Plainfield | Sullivan County | 2,570 |
| Pittsburg | Coos County | 852 |
| Piermont | Grafton County | 758 |