46 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Thompson | 1 | 16,748 | 16,555 | 0.07% | 199 | 84 | Town |
| Fallsburg | 2 | 15,189 | 14,049 | 1.13% | 196 | 78 | Town |
| Mamakating | 3 | 12,725 | 12,650 | 0.03% | 132 | 96 | Town |
| Liberty | 4 | 10,337 | 10,170 | -0.46% | 130 | 80 | Town |
| Monticello | 5 | 7,225 | 7,240 | -0.04% | 1,770 | 4 | Village |
| Liberty | 6 | 5,163 | 5,028 | 0.53% | 1,970 | 3 | Village |
| Bethel | 7 | 4,298 | 3,957 | 2.09% | 50 | 85 | Town |
| Neversink | 8 | 3,387 | 3,370 | 0.15% | 41 | 83 | Town |
| Rockland | 9 | 3,358 | 3,279 | 0.36% | 36 | 94 | Town |
| Callicoon | 10 | 3,053 | 2,988 | 0.03% | 63 | 49 | Town |
| Rock Hill | 11 | 2,544 | 2,204 | 2.13% | 296 | 9 | CDP |
| Fallsburg | 12 | 2,495 | 1,104 | 7.13% | 740 | 3 | CDP |
| Lumberland | 13 | 2,313 | 2,242 | 0.35% | 50 | 47 | Town |
| Delaware | 14 | 2,212 | 2,197 | 0.14% | 63 | 35 | Town |
| Loch Sheldrake | 15 | 2,029 | 1,588 | 7.13% | 1,227 | 2 | CDP |
| Hurleyville | 16 | 1,726 | 1,386 | 7.14% | 1,538 | 1 | CDP |
| South Fallsburg | 17 | 1,705 | 1,312 | -4.37% | 535 | 3 | CDP |
| Tusten | 18 | 1,456 | 1,407 | 0.69% | 31 | 47 | Town |
| Cochecton | 19 | 1,437 | 1,446 | -0.35% | 40 | 36 | Town |
| Fremont | 20 | 1,146 | 1,156 | -0.35% | 23 | 50 | Town |
| Wurtsboro | 21 | 1,085 | 1,090 | -0.09% | 869 | 1 | Village |
| Bloomingburg | 22 | 976 | 985 | -0.2% | 1,419 | 1 | Village |
| Forestburgh | 23 | 824 | 807 | 0.37% | 15 | 55 | Town |
| Livingston Manor | 24 | 773 | 928 | -3.74% | 238 | 3 | CDP |
| Woodridge | 25 | 709 | 709 | 0% | 424 | 2 | Village |
| Smallwood | 26 | 687 | 619 | 1.03% | 286 | 2 | CDP |
| Kauneonga Lake | 27 | 674 | 338 | 7.15% | 589 | 1 | CDP |
| Woodbourne | 28 | 585 | 537 | 7.14% | 811 | 1 | CDP |
| Grahamsville | 29 | 534 | 450 | 7.23% | 363 | 1 | CDP |
| Wurtsboro Hills | 30 | 442 | 322 | 7.02% | 373 | 1 | CDP |
| Roscoe | 31 | 417 | 489 | -2.11% | 428 | 1 | CDP |
| Kiamesha Lake | 32 | 401 | 191 | 7.22% | 393 | 1 | CDP |
| Barryville | 33 | 393 | 188 | 7.38% | 579 | 1 | CDP |
| Jeffersonville | 34 | 391 | 391 | 0% | 958 | 0 | Village |
| Narrowsburg | 35 | 365 | 372 | -1.08% | 202 | 2 | CDP |
| Lake Huntington | 36 | 339 | 232 | 7.28% | 284 | 1 | CDP |
| Mountain Dale | 37 | 325 | 377 | 7.26% | 56 | 6 | CDP |
| Swan Lake | 38 | 311 | 248 | 7.24% | 182 | 2 | CDP |
| Hortonville | 39 | 298 | 269 | 1.71% | 394 | 1 | CDP |
| Mongaup Valley | 40 | 265 | 689 | 7.29% | 53 | 5 | CDP |
| Callicoon | 41 | 240 | 559 | 2.13% | 386 | 1 | CDP |
| Eldred | 42 | 239 | 243 | 7.17% | 184 | 1 | CDP |
| Hankins | 43 | 166 | 124 | 7.1% | 121 | 1 | CDP |
| White Lake | 44 | 142 | 118 | 6.77% | 69 | 2 | CDP |
| Bridgeville | 45 | 140 | 224 | 6.87% | 84 | 2 | CDP |
| White Lake | 46 | 106 | 68 | 7.07% | 120 | 1 | CDP |
Thompson is the largest city in Sullivan County, with a population of 16,748.
White Lake is the smallest city in Sullivan County, with a population of 106.
There are 46 cities in Sullivan County, New York.