Identifiers: CDP
| Rank | Community | Population |
|---|---|---|
| 1 | Brentwood (CDP), NY | 62,387 |
| 2 | Coram (CDP), NY | 40,220 |
| 3 | Central Islip (CDP), NY | 36,714 |
| 4 | Commack (CDP), NY | 36,536 |
| 5 | Centereach (CDP), NY | 30,980 |
| 6 | Bay Shore (CDP), NY | 29,244 |
| 7 | Deer Park (CDP), NY | 28,837 |
| 8 | West Islip (CDP), NY | 27,048 |
| 9 | Holbrook (CDP), NY | 26,487 |
| 10 | Shirley (CDP), NY | 26,360 |
| 11 | Dix Hills (CDP), NY | 26,180 |
| 12 | Smithtown (CDP), NY | 25,629 |
| 13 | Medford (CDP), NY | 24,247 |
| 14 | East Patchogue (CDP), NY | 21,580 |
| 15 | Selden (CDP), NY | 21,262 |
| 16 | Hauppauge (CDP), NY | 20,083 |
| 17 | East Northport (CDP), NY | 20,048 |
| 18 | North Bay Shore (CDP), NY | 19,619 |
| 19 | Melville (CDP), NY | 19,284 |
| 20 | Ronkonkoma (CDP), NY | 18,955 |