46 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Thompson town | 1 | 16,555 | 16,551 | -0.36% | 197 | 84.09 | Town |
| Fallsburg town | 2 | 15,195 | 14,051 | 1.27% | 196 | 77.62 | Town |
| Mamakating town | 3 | 12,550 | 12,645 | -0.44% | 131 | 96.11 | Town |
| Liberty town | 4 | 10,385 | 10,161 | 0.04% | 130 | 79.58 | Town |
| Monticello | 5 | 7,210 | 7,237 | -0.07% | 1,767 | 4.08 | Village |
| Liberty | 6 | 5,201 | 5,023 | 0.7% | 1,984 | 2.62 | Village |
| Bethel town | 7 | 4,367 | 3,952 | 3.09% | 51 | 85.27 | Town |
| Rockland town | 8 | 3,328 | 3,285 | -0.03% | 35 | 94.16 | Town |
| Neversink town | 9 | 3,322 | 3,369 | -0.69% | 40 | 82.77 | Town |
| Callicoon town | 10 | 3,066 | 2,992 | 0.33% | 63 | 48.59 | Town |
| Rock Hill | 11 | 2,544 | 2,204 | 2.13% | 296 | 8.59 | CDP |
| Fallsburg | 12 | 2,495 | 1,104 | 7.13% | 740 | 3.37 | CDP |
| Lumberland town | 13 | 2,326 | 2,243 | 0.82% | 50 | 46.54 | Town |
| Delaware town | 14 | 2,176 | 2,198 | -0.5% | 62 | 34.90 | Town |
| Loch Sheldrake | 15 | 2,029 | 1,588 | 7.13% | 1,227 | 1.65 | CDP |
| Hurleyville | 16 | 1,726 | 1,386 | 7.14% | 1,538 | 1.12 | CDP |
| South Fallsburg | 17 | 1,705 | 1,312 | -4.37% | 535 | 3.19 | CDP |
| Tusten town | 18 | 1,431 | 1,405 | 0.07% | 30 | 47.20 | Town |
| Cochecton town | 19 | 1,426 | 1,445 | -0.56% | 39 | 36.30 | Town |
| Fremont town | 20 | 1,135 | 1,156 | -0.7% | 23 | 50.19 | Town |
| Wurtsboro | 21 | 1,071 | 1,085 | -0.28% | 857 | 1.25 | Village |
| Bloomingburg | 22 | 977 | 984 | -0.1% | 1,420 | 0.69 | Village |
| Forestburgh town | 23 | 819 | 809 | 0.12% | 15 | 54.78 | Town |
| Livingston Manor | 24 | 773 | 928 | -3.74% | 238 | 3.25 | CDP |
| Woodridge | 25 | 711 | 710 | 0% | 425 | 1.67 | Village |
| Smallwood | 26 | 687 | 619 | 1.03% | 286 | 2.40 | CDP |
| Kauneonga Lake | 27 | 674 | 338 | 7.15% | 589 | 1.15 | CDP |
| Woodbourne | 28 | 585 | 537 | 7.14% | 811 | 0.72 | CDP |
| Grahamsville | 29 | 534 | 450 | 7.23% | 363 | 1.47 | CDP |
| Wurtsboro Hills | 30 | 442 | 322 | 7.02% | 373 | 1.19 | CDP |
| Roscoe | 31 | 417 | 489 | -2.11% | 428 | 0.97 | CDP |
| Kiamesha Lake | 32 | 401 | 191 | 7.22% | 393 | 1.02 | CDP |
| Barryville | 33 | 393 | 188 | 7.38% | 579 | 0.68 | CDP |
| Jeffersonville | 34 | 392 | 392 | 0% | 961 | 0.41 | Village |
| Narrowsburg | 35 | 365 | 372 | -1.08% | 202 | 1.81 | CDP |
| Lake Huntington | 36 | 339 | 232 | 7.28% | 284 | 1.20 | CDP |
| Mountain Dale | 37 | 325 | 377 | 7.26% | 56 | 5.79 | CDP |
| Swan Lake | 38 | 311 | 248 | 7.24% | 182 | 1.71 | CDP |
| Hortonville | 39 | 298 | 269 | 1.71% | 394 | 0.76 | CDP |
| Mongaup Valley | 40 | 265 | 689 | 7.29% | 53 | 5.02 | CDP |
| Callicoon | 41 | 240 | 559 | 2.13% | 386 | 0.62 | CDP |
| Eldred | 42 | 239 | 243 | 7.17% | 184 | 1.30 | CDP |
| Hankins | 43 | 166 | 124 | 7.1% | 121 | 1.37 | CDP |
| White Lake | 44 | 142 | 118 | 6.77% | 69 | 2.05 | CDP |
| Bridgeville | 45 | 140 | 224 | 6.87% | 84 | 1.67 | CDP |
| White Lake | 46 | 106 | 68 | 7.07% | 120 | 0.89 | CDP |
Thompson town is the largest city in Sullivan County, with a population of 16,555.
White Lake is the smallest city in Sullivan County.
There are 46 cities in Sullivan County, New York.