63 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Le Ray | 1 | 24,207 | 25,501 | -0.28% | 329 | 74 | Town |
| Watertown | 2 | 23,909 | 24,553 | -0.54% | 2,647 | 9 | City |
| Fort Drum | 3 | 17,134 | 13,034 | 1.66% | 1,195 | 14 | CDP |
| Brownville | 4 | 5,756 | 5,815 | -0.21% | 98 | 59 | Town |
| Wilna | 5 | 5,576 | 5,697 | -0.39% | 72 | 78 | Town |
| Watertown | 6 | 5,453 | 5,827 | -0.2% | 153 | 36 | Town |
| Adams | 7 | 4,875 | 4,945 | -0.37% | 115 | 42 | Town |
| Clayton | 8 | 4,600 | 4,729 | -0.67% | 56 | 83 | Town |
| Champion | 9 | 4,479 | 4,542 | -0.4% | 102 | 44 | Town |
| Alexandria | 10 | 3,671 | 3,722 | -0.38% | 51 | 73 | Town |
| Calcium | 11 | 3,655 | 3,548 | 0.3% | 652 | 6 | CDP |
| Ellisburg | 12 | 3,300 | 3,342 | -0.33% | 39 | 85 | Town |
| Pamelia | 13 | 3,262 | 3,328 | -0.37% | 96 | 34 | Town |
| Carthage | 14 | 3,242 | 3,317 | -0.46% | 1,337 | 2 | Village |
| Hounsfield | 15 | 3,226 | 3,263 | -0.34% | 66 | 49 | Town |
| Rutland | 16 | 2,970 | 3,020 | -0.4% | 66 | 45 | Town |
| Orleans | 17 | 2,757 | 2,783 | -0.25% | 39 | 71 | Town |
| Theresa | 18 | 2,613 | 2,641 | -0.34% | 40 | 65 | Town |
| Cape Vincent | 19 | 2,550 | 2,684 | 0.35% | 45 | 56 | Town |
| Lyme | 20 | 2,220 | 2,288 | -0.72% | 40 | 56 | Town |
| Philadelphia | 21 | 1,954 | 1,968 | 0.1% | 52 | 38 | Town |
| West Carthage | 22 | 1,744 | 1,767 | -0.29% | 1,333 | 1 | Village |
| Clayton | 23 | 1,678 | 1,731 | -0.65% | 1,047 | 2 | Village |
| Adams | 24 | 1,667 | 1,687 | -0.24% | 1,154 | 1 | Village |
| Antwerp | 25 | 1,660 | 1,678 | -0.3% | 16 | 106 | Town |
| Henderson | 26 | 1,419 | 1,436 | -0.35% | 34 | 41 | Town |
| Sackets Harbor | 27 | 1,361 | 1,376 | -0.22% | 590 | 2 | Village |
| Great Bend | 28 | 1,299 | 1,329 | 2.36% | 224 | 6 | CDP |
| Black River | 29 | 1,229 | 1,261 | -0.57% | 690 | 2 | Village |
| Rodman | 30 | 1,178 | 1,192 | -0.25% | 28 | 42 | Town |
| Philadelphia | 31 | 1,135 | 1,172 | -0.7% | 1,185 | 1 | Village |
| Dexter | 32 | 1,011 | 1,009 | 0% | 1,518 | 1 | Village |
| Alexandria Bay | 33 | 939 | 953 | -0.32% | 1,254 | 1 | Village |
| Brownville | 34 | 925 | 937 | -0.32% | 1,482 | 1 | Village |
| Lorraine | 35 | 900 | 917 | -0.44% | 23 | 39 | Town |
| Pamelia Center | 36 | 896 | 441 | 4.92% | 640 | 1 | CDP |
| Adams Center | 37 | 886 | 1,000 | -4.83% | 182 | 5 | CDP |
| Theresa | 38 | 737 | 760 | -0.67% | 584 | 1 | Village |
| Cape Vincent | 39 | 724 | 736 | -0.41% | 1,030 | 1 | Village |
| Evans Mills | 40 | 610 | 623 | -0.49% | 747 | 1 | Village |
| Chaumont | 41 | 591 | 610 | -0.67% | 601 | 1 | Village |
| Antwerp | 42 | 510 | 517 | -0.39% | 508 | 1 | Village |
| La Fargeville | 43 | 510 | 733 | -1.35% | 154 | 3 | CDP |
| Felts Mills | 44 | 444 | 451 | 0.91% | 758 | 1 | CDP |
| Glen Park | 45 | 444 | 447 | -0.22% | 622 | 1 | Village |
| Pierrepont Manor | 46 | 404 | 416 | 3.06% | 522 | 1 | CDP |
| Depauville | 47 | 341 | 224 | -4.21% | 35 | 10 | CDP |
| Mannsville | 48 | 319 | 324 | -0.31% | 356 | 1 | Village |
| Belleville | 49 | 305 | 279 | 1.67% | 464 | 1 | CDP |
| Plessis | 50 | 292 | 370 | 3.18% | 844 | 0 | CDP |
| Thousand Island Park | 51 | 270 | 155 | 7.14% | 909 | 0 | CDP |
| Deferiet | 52 | 255 | 258 | -0.39% | 378 | 1 | Village |
| Henderson | 53 | 241 | 236 | 0.42% | 459 | 1 | CDP |
| Redwood | 54 | 229 | 483 | -9.84% | 116 | 2 | CDP |
| Ellisburg | 55 | 210 | 214 | -0.47% | 210 | 1 | Village |
| Rodman | 56 | 203 | 142 | 1.5% | 1,277 | 0 | CDP |
| Worth | 57 | 199 | 200 | 0% | 5 | 43 | Town |
| Natural Bridge | 58 | 132 | 228 | -10.81% | 103 | 1 | CDP |
| Oxbow | 59 | 120 | 122 | 0% | 297 | 0 | CDP |
| Lorraine | 60 | 99 | 55 | -4.81% | 202 | 0 | CDP |
| Fishers Landing | 61 | 68 | 76 | 7.94% | 151 | 0 | CDP |
| Herrings | 62 | 41 | 132 | 7.89% | 266 | 0 | CDP |
| Three Mile Bay | 63 | 22 | 182 | -38.89% | 78 | 0 | CDP |
Le Ray is the largest city in Jefferson County, with a population of 24,207.
Three Mile Bay is the smallest city in Jefferson County, with a population of 22.
There are 63 cities in Jefferson County, New York.