12 cities
| City | County | 2025 Pop. ↓ |
|---|---|---|
| Derry town | Rockingham County | 33,908 |
| Dover city | Strafford County | 33,705 |
| Durham town | Strafford County | 14,917 |
| Deerfield town | Rockingham County | 4,971 |
| Danville town | Rockingham County | 4,678 |
| Dunbarton town | Merrimack County | 3,204 |
| Deering town | Hillsborough County | 1,925 |
| Dublin town | Cheshire County | 1,594 |
| Danbury town | Merrimack County | 1,324 |
| Dalton town | Coos County | 908 |
| Dorchester town | Grafton County | 336 |
| Dummer town | Coos County | 321 |