36 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Derry | 1 | 34,156 | 34,080 | 0.14% | 963 | 35 | Town |
| Salem | 2 | 31,913 | 30,288 | 0.38% | 1,285 | 25 | Town |
| Londonderry | 3 | 27,461 | 26,104 | 0.66% | 654 | 42 | Town |
| Portsmouth | 4 | 23,288 | 21,991 | 0.76% | 1,487 | 16 | City |
| Hampton | 5 | 16,486 | 16,233 | 0.12% | 1,277 | 13 | Town |
| Windham | 6 | 16,480 | 15,837 | 0.83% | 616 | 27 | Town |
| Exeter | 7 | 16,295 | 16,051 | 0.28% | 831 | 20 | Town |
| Raymond | 8 | 11,096 | 10,698 | 0.38% | 385 | 29 | Town |
| Newmarket | 9 | 9,616 | 9,423 | 0.46% | 764 | 13 | Town |
| Hampstead | 10 | 9,214 | 9,004 | 0.32% | 687 | 13 | Town |
| Seabrook | 11 | 8,492 | 8,405 | 0.35% | 946 | 9 | Town |
| Epping | 12 | 8,283 | 7,152 | 3.02% | 318 | 26 | Town |
| Plaistow | 13 | 7,951 | 7,838 | 0.51% | 751 | 11 | Town |
| Stratham | 14 | 7,763 | 7,692 | 0.04% | 512 | 15 | Town |
| Atkinson | 15 | 7,373 | 7,097 | 0.12% | 661 | 11 | Town |
| Sandown | 16 | 6,841 | 6,553 | 0.9% | 491 | 14 | Town |
| Auburn | 17 | 6,427 | 5,975 | 1.29% | 254 | 25 | Town |
| Kingston | 18 | 6,315 | 6,193 | 0.17% | 319 | 20 | Town |
| Rye | 19 | 5,749 | 5,546 | 0.75% | 455 | 13 | Town |
| Nottingham | 20 | 5,617 | 5,245 | 1.34% | 121 | 46 | Town |
| Chester | 21 | 5,352 | 5,239 | 0.28% | 206 | 26 | Town |
| Deerfield | 22 | 5,035 | 4,862 | 0.52% | 99 | 51 | Town |
| Fremont | 23 | 4,987 | 4,745 | 0.89% | 290 | 17 | Town |
| Brentwood | 24 | 4,919 | 4,505 | 1.36% | 293 | 17 | Town |
| Newton | 25 | 4,871 | 4,819 | 0.29% | 496 | 10 | Town |
| Northwood | 26 | 4,750 | 4,643 | 0.51% | 169 | 28 | Town |
| Danville | 27 | 4,723 | 4,415 | 1.05% | 405 | 12 | Town |
| North Hampton | 28 | 4,539 | 4,539 | 0% | 327 | 14 | Town |
| Candia | 29 | 4,314 | 4,017 | 1.13% | 142 | 30 | Town |
| Greenland | 30 | 4,170 | 4,066 | 0.53% | 398 | 10 | Town |
| East Kingston | 31 | 2,436 | 2,438 | 0% | 246 | 10 | Town |
| Hampton Falls | 32 | 2,402 | 2,404 | 0.13% | 197 | 12 | Town |
| Kensington | 33 | 2,101 | 2,095 | 0.14% | 176 | 12 | Town |
| Newfields | 34 | 1,793 | 1,774 | 0.34% | 253 | 7 | Town |
| New Castle | 35 | 1,009 | 993 | 0.4% | 1,247 | 1 | Town |
| South Hampton | 36 | 893 | 889 | 0% | 111 | 8 | Town |
Derry is the largest city in Rockingham County, with a population of 34,156.
South Hampton is the smallest city in Rockingham County, with a population of 893.
There are 36 cities in Rockingham County, New Hampshire.