37 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Derry | 1 | 34,109 | 34,080 | 0.14% | 962 | 35 | Town |
| Salem | 2 | 31,793 | 30,288 | 0.38% | 1,280 | 25 | Town |
| Londonderry | 3 | 27,281 | 26,104 | 0.66% | 650 | 42 | Town |
| Portsmouth | 4 | 23,174 | 21,991 | 1.03% | 1,480 | 16 | City |
| Portsmouth | 5 | 23,113 | 21,991 | 0.76% | 1,476 | 16 | City |
| Hampton | 6 | 16,467 | 16,233 | 0.12% | 1,275 | 13 | Town |
| Windham | 7 | 16,344 | 15,837 | 0.84% | 611 | 27 | Town |
| Exeter | 8 | 16,250 | 16,051 | 0.28% | 829 | 20 | Town |
| Raymond | 9 | 11,054 | 10,698 | 0.38% | 384 | 29 | Town |
| Newmarket | 10 | 9,572 | 9,423 | 0.46% | 760 | 13 | Town |
| Hampstead | 11 | 9,185 | 9,004 | 0.32% | 684 | 13 | Town |
| Seabrook | 12 | 8,462 | 8,405 | 0.36% | 943 | 9 | Town |
| Epping | 13 | 8,040 | 7,152 | 3.12% | 309 | 26 | Town |
| Plaistow | 14 | 7,911 | 7,838 | 0.51% | 747 | 11 | Town |
| Stratham | 15 | 7,760 | 7,692 | 0.04% | 512 | 15 | Town |
| Atkinson | 16 | 7,364 | 7,097 | 0.12% | 660 | 11 | Town |
| Sandown | 17 | 6,780 | 6,553 | 0.91% | 487 | 14 | Town |
| Auburn | 18 | 6,345 | 5,975 | 1.31% | 250 | 25 | Town |
| Kingston | 19 | 6,304 | 6,193 | 0.17% | 318 | 20 | Town |
| Rye | 20 | 5,706 | 5,546 | 0.76% | 451 | 13 | Town |
| Nottingham | 21 | 5,543 | 5,245 | 1.35% | 119 | 46 | Town |
| Chester | 22 | 5,337 | 5,239 | 0.28% | 205 | 26 | Town |
| Deerfield | 23 | 5,009 | 4,862 | 0.52% | 99 | 51 | Town |
| Fremont | 24 | 4,943 | 4,745 | 0.9% | 288 | 17 | Town |
| Newton | 25 | 4,857 | 4,819 | 0.29% | 495 | 10 | Town |
| Brentwood | 26 | 4,853 | 4,505 | 1.38% | 289 | 17 | Town |
| Northwood | 27 | 4,726 | 4,643 | 0.51% | 168 | 28 | Town |
| Danville | 28 | 4,674 | 4,415 | 1.06% | 401 | 12 | Town |
| North Hampton | 29 | 4,539 | 4,539 | 0% | 327 | 14 | Town |
| Candia | 30 | 4,266 | 4,017 | 1.14% | 141 | 30 | Town |
| Greenland | 31 | 4,148 | 4,066 | 0.53% | 396 | 10 | Town |
| East Kingston | 32 | 2,436 | 2,438 | 0% | 246 | 10 | Town |
| Hampton Falls | 33 | 2,399 | 2,404 | 0.13% | 196 | 12 | Town |
| Kensington | 34 | 2,098 | 2,095 | 0.14% | 175 | 12 | Town |
| Newfields | 35 | 1,787 | 1,774 | 0.34% | 252 | 7 | Town |
| New Castle | 36 | 1,005 | 993 | 0.4% | 1,242 | 1 | Town |
| South Hampton | 37 | 893 | 889 | 0% | 111 | 8 | Town |
Derry is the largest city in Rockingham County, with a population of 34,109.
South Hampton is the smallest city in Rockingham County, with a population of 893.
There are 37 cities in Rockingham County, New Hampshire.