| Zip Code | City | Population ↓ |
|---|---|---|
| 13601 | Watertown | 38,332 |
| 13603 | Watertown | 14,050 |
| 13619 | Carthage | 10,625 |
| 13605 | Adams | 5,261 |
| 13624 | Clayton | 4,933 |
| 13637 | Evans Mills | 4,493 |
| 13634 | Dexter | 3,947 |
| 13656 | La Fargeville | 3,230 |
| 13691 | Theresa | 3,123 |
| 13602 | Fort Drum | 2,798 |
| 13612 | Black River | 2,703 |
| 13606 | Adams Center | 2,423 |
| 13685 | Sackets Harbor | 2,187 |
| 13673 | Philadelphia | 2,163 |
| 13622 | Chaumont | 1,985 |
| 13616 | Calcium | 1,936 |
| 13661 | Mannsville | 1,825 |
| 13608 | Antwerp | 1,818 |
| 13618 | Cape Vincent | 1,814 |
| 13607 | Alexandria Bay | 1,750 |
| 13650 | Henderson | 1,355 |
| 13679 | Redwood | 1,108 |
| 13682 | Rodman | 845 |
| 13615 | Brownville | 586 |
| 13659 | Lorraine | 379 |
| 13638 | Felts Mills | 372 |
| 13611 | Belleville | 312 |
| 13640 | Wellesley Island | 302 |
| 13693 | Three Mile Bay | 294 |
| 13628 | Deferiet | 268 |
| 13692 | Thousand Island Park | 216 |
| 13636 | Ellisburg | 177 |
| 13674 | Pierrepont Manor | 137 |
| 13651 | Henderson Harbor | 126 |
| 13632 | Depauville | 107 |
| 13675 | Plessis | 61 |
| 13643 | Great Bend | 60 |
| 13641 | Fishers Landing | 54 |
The data shown reflect ZCTAs from the US Census. As of 2024, there are 38 ZCTAs in Jefferson County, New York (US Census).