38 ZIP Codes
| Zip Code | City | Population ↓ |
|---|---|---|
| 13601 | Watertown | 36,839 |
| 13603 | Watertown | 14,136 |
| 13619 | Carthage | 10,578 |
| 13605 | Adams | 5,259 |
| 13637 | Evans Mills | 5,212 |
| 13624 | Clayton | 4,650 |
| 13634 | Dexter | 3,570 |
| 13691 | Theresa | 2,990 |
| 13656 | La Fargeville | 2,942 |
| 13612 | Black River | 2,865 |
| 13606 | Adams Center | 2,468 |
| 13602 | Fort Drum | 2,440 |
| 13685 | Sackets Harbor | 2,362 |
| 13673 | Philadelphia | 2,097 |
| 13607 | Alexandria Bay | 2,020 |
| 13661 | Mannsville | 1,908 |
| 13622 | Chaumont | 1,859 |
| 13618 | Cape Vincent | 1,771 |
| 13608 | Antwerp | 1,676 |
| 13616 | Calcium | 1,430 |
| 13650 | Henderson | 1,236 |
| 13679 | Redwood | 1,205 |
| 13682 | Rodman | 854 |
| 13615 | Brownville | 700 |
| 13693 | Three Mile Bay | 423 |
| 13659 | Lorraine | 386 |
| 13628 | Deferiet | 330 |
| 13640 | Wellesley Island | 318 |
| 13692 | Thousand Island Park | 222 |
| 13643 | Great Bend | 193 |
| 13674 | Pierrepont Manor | 178 |
| 13638 | Felts Mills | 157 |
| 13651 | Henderson Harbor | 147 |
| 13611 | Belleville | 147 |
| 13636 | Ellisburg | 141 |
| 13632 | Depauville | 118 |
| 13641 | Fishers Landing | 91 |
| 13675 | Plessis | 54 |
The data shown reflect ZCTAs from the US Census. As of 2025, there are 38 ZCTAs in Jefferson County, New York (US Census).