27 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Berlin | 1 | 9,494 | 9,406 | 0.19% | 155 | 61.35 | City |
| Berlin city | 2 | 9,317 | 9,406 | -0.76% | 152 | 61.35 | City |
| Lancaster town | 3 | 3,211 | 3,212 | -0.37% | 64 | 49.97 | Town |
| Gorham town | 4 | 2,648 | 2,693 | -0.6% | 83 | 31.83 | Town |
| Whitefield town | 5 | 2,578 | 2,492 | 0.98% | 75 | 34.26 | Town |
| Lancaster | 6 | 2,394 | 1,892 | 1.92% | 804 | 2.98 | CDP |
| Gorham | 7 | 2,154 | 1,948 | 1.75% | 1,280 | 1.68 | CDP |
| Colebrook town | 8 | 2,108 | 2,081 | 0.09% | 52 | 40.51 | Town |
| Northumberland town | 9 | 2,084 | 2,126 | -0.81% | 58 | 35.69 | Town |
| Whitefield | 10 | 1,379 | 1,202 | 1.1% | 865 | 1.59 | CDP |
| Milan town | 11 | 1,368 | 1,357 | 0% | 21 | 63.69 | Town |
| Jefferson town | 12 | 1,067 | 1,045 | 0.19% | 21 | 49.99 | Town |
| Colebrook | 13 | 1,026 | 1,037 | -2.38% | 392 | 2.62 | CDP |
| Dalton town | 14 | 908 | 928 | -0.77% | 33 | 27.53 | Town |
| Pittsburg town | 15 | 843 | 805 | 0.6% | 3 | 281.32 | Town |
| Carroll town | 16 | 830 | 819 | -0.12% | 17 | 50.27 | Town |
| Groveton | 17 | 769 | 914 | -2.9% | 373 | 2.06 | CDP |
| Stewartstown town | 18 | 765 | 807 | -0.52% | 17 | 46.25 | Town |
| Columbia town | 19 | 676 | 661 | 0.75% | 11 | 60.77 | Town |
| Stratford town | 20 | 649 | 661 | -0.61% | 8 | 79.24 | Town |
| West Stewartstown | 21 | 485 | 325 | 1.46% | 784 | 0.62 | CDP |
| Stark town | 22 | 460 | 473 | -0.86% | 8 | 58.81 | Town |
| Shelburne town | 23 | 354 | 353 | -0.56% | 7 | 47.92 | Town |
| Dummer town | 24 | 321 | 304 | 1.26% | 7 | 47.96 | Town |
| Randolph town | 25 | 321 | 329 | -0.93% | 7 | 47.04 | Town |
| Errol town | 26 | 289 | 299 | -1.03% | 5 | 60.35 | Town |
| Clarksville town | 27 | 280 | 289 | -1.06% | 5 | 60.33 | Town |
Berlin is the largest city in Coos County, with a population of 9,494.
Clarksville town is the smallest city in Coos County.
There are 27 cities in Coos County, New Hampshire.