29 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Concord | 1 | 44,832 | 44,040 | 0.35% | 701 | 64 | City |
| Concord | 2 | 44,768 | 44,040 | 0.21% | 700 | 64 | City |
| Hooksett | 3 | 15,495 | 14,907 | 0.77% | 430 | 36 | Town |
| Franklin | 4 | 8,841 | 8,748 | 0.2% | 322 | 27 | City |
| Franklin | 5 | 8,840 | 8,748 | 0.19% | 322 | 27 | City |
| Bow | 6 | 8,410 | 8,246 | 0.15% | 299 | 28 | Town |
| Pembroke | 7 | 7,617 | 7,206 | 0.66% | 337 | 23 | Town |
| Henniker | 8 | 6,287 | 6,190 | 0.32% | 143 | 44 | Town |
| Hopkinton | 9 | 6,206 | 5,929 | 0.98% | 143 | 43 | Town |
| Loudon | 10 | 5,755 | 5,591 | 0.26% | 125 | 46 | Town |
| Northfield | 11 | 5,114 | 4,877 | 0.95% | 179 | 29 | Town |
| Epsom | 12 | 5,058 | 4,839 | 0.76% | 147 | 34 | Town |
| Allenstown | 13 | 4,772 | 4,712 | 0.15% | 233 | 20 | Town |
| New London | 14 | 4,470 | 4,409 | 0.22% | 200 | 22 | Town |
| Boscawen | 15 | 4,211 | 4,005 | 1.4% | 169 | 25 | Town |
| Pittsfield | 16 | 4,153 | 4,078 | 0.27% | 173 | 24 | Town |
| Dunbarton | 17 | 3,251 | 3,013 | 2.04% | 105 | 31 | Town |
| Warner | 18 | 2,980 | 2,936 | 0.34% | 54 | 55 | Town |
| Chichester | 19 | 2,852 | 2,669 | 1.46% | 135 | 21 | Town |
| Canterbury | 20 | 2,480 | 2,387 | 0.53% | 57 | 44 | Town |
| Andover | 21 | 2,468 | 2,404 | 0.73% | 61 | 40 | Town |
| Newbury | 22 | 2,320 | 2,176 | 1.22% | 65 | 36 | Town |
| Sutton | 23 | 2,096 | 1,984 | 1.4% | 49 | 43 | Town |
| Webster | 24 | 1,991 | 1,923 | 0.61% | 71 | 28 | Town |
| Bradford | 25 | 1,725 | 1,661 | 0.17% | 49 | 35 | Town |
| Salisbury | 26 | 1,514 | 1,427 | 0.66% | 38 | 40 | Town |
| Wilmot | 27 | 1,478 | 1,409 | 0.48% | 50 | 29 | Town |
| Danbury | 28 | 1,310 | 1,258 | 0.54% | 35 | 38 | Town |
| Hill | 29 | 1,058 | 1,015 | 0.76% | 40 | 27 | Town |
Concord is the largest city in Merrimack County, with a population of 44,832.
Hill is the smallest city in Merrimack County, with a population of 1,058.
There are 29 cities in Merrimack County, New Hampshire.