43 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Brookhaven | 1 | 497,541 | 484,592 | 0.48% | 1,916 | 260 | Town |
| Islip | 2 | 341,430 | 339,101 | 0.33% | 3,308 | 103 | Town |
| Babylon | 3 | 220,044 | 217,662 | 0.34% | 4,209 | 52 | Town |
| Huntington | 4 | 206,780 | 203,614 | 0.5% | 2,199 | 94 | Town |
| Smithtown | 5 | 116,940 | 115,898 | 0.31% | 2,176 | 54 | Town |
| Southampton | 6 | 71,948 | 68,869 | 0.91% | 518 | 139 | Town |
| Riverhead | 7 | 36,403 | 35,864 | 0.46% | 540 | 67 | Town |
| East Hampton | 8 | 29,550 | 28,342 | 0.78% | 397 | 74 | Town |
| Lindenhurst | 9 | 27,194 | 27,092 | 0.06% | 7,258 | 4 | Village |
| Southold | 10 | 24,365 | 23,742 | 0.58% | 453 | 54 | Town |
| Patchogue | 11 | 12,483 | 12,374 | 0.14% | 5,523 | 2 | Village |
| Babylon | 12 | 12,205 | 12,168 | 0.05% | 5,062 | 2 | Village |
| Lake Grove | 13 | 11,144 | 11,039 | 0.16% | 3,783 | 3 | Village |
| Amityville | 14 | 9,841 | 9,471 | 0.63% | 4,786 | 2 | Village |
| Port Jefferson | 15 | 8,299 | 7,969 | 0.67% | 2,709 | 3 | Village |
| Northport | 16 | 7,310 | 7,330 | -0.04% | 3,174 | 2 | Village |
| Southampton | 17 | 4,767 | 4,544 | 0.78% | 731 | 7 | Village |
| Greenport | 18 | 4,264 | 4,461 | -1% | 229 | 19 | Town |
| Islandia | 19 | 3,693 | 3,566 | 0.57% | 1,668 | 2 | Village |
| Lloyd Harbor | 20 | 3,565 | 3,565 | 0% | 382 | 9 | Village |
| Shelter Island | 21 | 3,374 | 3,235 | 0.87% | 277 | 12 | Town |
| Brightwaters | 22 | 3,189 | 3,182 | 0.03% | 3,301 | 1 | Village |
| Sag Harbor | 23 | 2,848 | 2,752 | 0.56% | 1,594 | 2 | Village |
| Greenport | 24 | 2,588 | 2,597 | -0.04% | 2,724 | 1 | Village |
| Westhampton Beach | 25 | 2,258 | 2,197 | 0.44% | 768 | 3 | Village |
| Bellport | 26 | 2,217 | 2,198 | 0.14% | 1,529 | 1 | Village |
| Village of the Branch | 27 | 1,760 | 1,768 | -0.06% | 1,853 | 1 | Village |
| Quogue | 28 | 1,727 | 1,636 | 0.88% | 414 | 4 | Village |
| Nissequogue | 29 | 1,636 | 1,603 | 0.37% | 430 | 4 | Village |
| East Hampton | 30 | 1,584 | 1,500 | 0.89% | 332 | 5 | Village |
| Head of the Harbor | 31 | 1,473 | 1,479 | -0.07% | 525 | 3 | Village |
| Huntington Bay | 32 | 1,455 | 1,424 | 0.34% | 1,458 | 1 | Village |
| North Haven | 33 | 1,221 | 1,148 | 0.99% | 460 | 3 | Village |
| Old Field | 34 | 933 | 908 | 0.43% | 451 | 2 | Village |
| Poquott | 35 | 930 | 927 | 0.11% | 2,123 | 0 | Village |
| Belle Terre | 36 | 790 | 783 | 0.13% | 893 | 1 | Village |
| Sagaponack | 37 | 749 | 733 | 0.4% | 170 | 4 | Village |
| Asharoken | 38 | 615 | 593 | 0.65% | 432 | 1 | Village |
| Shoreham | 39 | 526 | 520 | 0.19% | 1,159 | 0 | Village |
| Ocean Beach | 40 | 177 | 171 | 0.57% | 1,255 | 0 | Village |
| West Hampton Dunes | 41 | 122 | 112 | 1.67% | 390 | 0 | Village |
| Saltaire | 42 | 110 | 107 | 0.92% | 472 | 0 | Village |
| Dering Harbor | 43 | 37 | 36 | 0% | 150 | 0 | Village |
Brookhaven is the largest city in Suffolk County, with a population of 497,541.
Dering Harbor is the smallest city in Suffolk County, with a population of 37.
There are 43 cities in Suffolk County, New York.