43 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Brookhaven | 1 | 485,982 | 484,578 | -0.24% | 1,872 | 259.64 | Town |
| Islip | 2 | 333,694 | 339,077 | -0.47% | 3,234 | 103.20 | Town |
| Babylon | 3 | 215,046 | 217,663 | -0.46% | 4,114 | 52.28 | Town |
| Huntington | 4 | 201,618 | 203,585 | -0.32% | 2,144 | 94.04 | Town |
| Smithtown | 5 | 114,524 | 115,897 | -0.41% | 2,131 | 53.75 | Town |
| Southampton | 6 | 70,022 | 68,842 | 0.23% | 504 | 138.84 | Town |
| Riverhead | 7 | 35,399 | 35,815 | -0.46% | 525 | 67.40 | Town |
| East Hampton | 8 | 29,006 | 28,363 | 0.42% | 390 | 74.36 | Town |
| Lindenhurst | 9 | 26,892 | 27,091 | -0.15% | 7,177 | 3.75 | Village |
| Southold | 10 | 23,684 | 23,735 | -0.36% | 441 | 53.75 | Town |
| Patchogue | 11 | 12,313 | 12,373 | -0.1% | 5,448 | 2.26 | Village |
| Babylon | 12 | 12,064 | 12,168 | -0.17% | 5,004 | 2.41 | Village |
| Lake Grove | 13 | 11,009 | 11,038 | -0.05% | 3,737 | 2.95 | Village |
| Amityville | 14 | 9,653 | 9,463 | 0.4% | 4,695 | 2.06 | Village |
| Port Jefferson | 15 | 8,239 | 7,963 | 0.67% | 2,690 | 3.06 | Village |
| Northport | 16 | 7,233 | 7,332 | -0.28% | 3,141 | 2.30 | Village |
| Southampton | 17 | 4,686 | 4,538 | 0.64% | 719 | 6.52 | Village |
| Greenport | 18 | 4,296 | 4,461 | -0.95% | 231 | 18.61 | Town |
| Islandia | 19 | 3,668 | 3,565 | 0.58% | 1,657 | 2.21 | Village |
| Lloyd Harbor | 20 | 3,519 | 3,563 | -0.26% | 377 | 9.33 | Village |
| Shelter Island | 21 | 3,318 | 3,253 | 0.39% | 272 | 12.20 | Town |
| Brightwaters | 22 | 3,160 | 3,182 | -0.13% | 3,271 | 0.97 | Village |
| Sag Harbor | 23 | 2,807 | 2,752 | 0.39% | 1,571 | 1.79 | Village |
| Greenport | 24 | 2,537 | 2,596 | -0.47% | 2,671 | 0.95 | Village |
| Westhampton Beach | 25 | 2,204 | 2,174 | 0.27% | 750 | 2.94 | Village |
| Bellport | 26 | 2,195 | 2,195 | 0% | 1,514 | 1.45 | Village |
| Village Branch | 27 | 1,738 | 1,765 | -0.29% | 1,829 | 0.95 | Village |
| Quogue | 28 | 1,722 | 1,659 | 0.76% | 413 | 4.17 | Village |
| Nissequogue | 29 | 1,608 | 1,603 | 0.06% | 422 | 3.81 | Village |
| East Hampton | 30 | 1,569 | 1,511 | 0.77% | 329 | 4.77 | Village |
| Head Harbor | 31 | 1,458 | 1,480 | -0.27% | 520 | 2.81 | Village |
| Huntington Bay | 32 | 1,426 | 1,425 | 0% | 1,429 | 1 | Village |
| North Haven | 33 | 1,192 | 1,149 | 0.76% | 449 | 2.65 | Village |
| Poquott | 34 | 921 | 928 | -0.11% | 2,103 | 0.44 | Village |
| Old Field | 35 | 893 | 908 | -0.34% | 431 | 2.07 | Village |
| Belle Terre | 36 | 785 | 784 | 0% | 887 | 0.89 | Village |
| Sagaponack | 37 | 739 | 731 | 0.27% | 168 | 4.41 | Village |
| Asharoken | 38 | 608 | 593 | 0.5% | 428 | 1.42 | Village |
| Shoreham | 39 | 522 | 521 | 0% | 1,150 | 0.45 | Village |
| Ocean Beach | 40 | 169 | 166 | 0.6% | 1,199 | 0.14 | Village |
| West Hampton Dunes | 41 | 119 | 114 | 0.85% | 380 | 0.31 | Village |
| Saltaire | 42 | 111 | 110 | 0% | 476 | 0.23 | Village |
| Dering Harbor | 43 | 35 | 34 | 0% | 142 | 0.25 | Village |
Brookhaven is the largest city in Suffolk County, with a population of 485,982.
Dering Harbor is the smallest city in Suffolk County.
There are 43 cities in Suffolk County, New York.