| Zip Code | City | Population ↓ |
|---|---|---|
| 4654 | Machias | 3,385 |
| 4619 | Calais | 3,078 |
| 4694 | Baileyville | 2,352 |
| 4668 | Princeton | 1,741 |
| 4652 | Lubec | 1,461 |
| 4630 | East Machias | 1,377 |
| 4658 | Milbridge | 1,369 |
| 4667 | Perry | 1,324 |
| 4666 | Pembroke | 1,324 |
| 4680 | Steuben | 1,248 |
| 4631 | Eastport | 1,211 |
| 4649 | Jonesport | 1,206 |
| 4606 | Addison | 1,192 |
| 4623 | Columbia Falls | 1,124 |
| 4424 | Danforth | 953 |
| 4655 | Machiasport | 924 |
| 4622 | Cherryfield | 868 |
| 4643 | Harrington | 845 |
| 4671 | Robbinston | 626 |
| 4648 | Jonesboro | 593 |
| 4626 | Cutler | 517 |
| 4691 | Whiting | 515 |
| 4611 | Beals | 513 |
| 4628 | Dennysville | 501 |
| 4657 | Meddybemps | 322 |
| 4490 | Topsfield | 238 |
| 4686 | Wesley | 191 |
| 4413 | Brookton | 170 |
| 4491 | Vanceboro | 154 |
| 4492 | Waite | 97 |
| 4454 | Lambert Lake | 5 |
The data shown reflect ZCTAs from the US Census. As of 2024, there are 31 ZCTAs in Washington County, Maine (US Census).