| Zip Code | City | Population ↓ |
|---|---|---|
| 4401 | Bangor | 44,285 |
| 4412 | Brewer | 9,633 |
| 4444 | Hampden | 9,303 |
| 4468 | Old Town | 9,234 |
| 4473 | Orono | 8,171 |
| 4457 | Lincoln | 5,794 |
| 4930 | Dexter | 4,226 |
| 4474 | Orrington | 3,820 |
| 4428 | Eddington | 3,500 |
| 4953 | Newport | 3,143 |
| 4461 | Milford | 3,073 |
| 4456 | Levant | 2,965 |
| 4469 | Orono | 2,958 |
| 4427 | Corinth | 2,916 |
| 4419 | Carmel | 2,902 |
| 4928 | Corinna | 1,925 |
| 4493 | West Enfield | 1,823 |
| 4418 | Greenbush | 1,785 |
| 4411 | Bradley | 1,693 |
| 4430 | East Millinocket | 1,541 |
| 4448 | Howland | 1,397 |
| 4450 | Kenduskeag | 1,370 |
| 4969 | Plymouth | 1,319 |
| 4488 | Stetson | 1,293 |
| 4460 | Medway | 1,200 |
| 4434 | Etna | 1,200 |
| 4932 | Dixmont | 1,186 |
| 4435 | Exeter | 1,170 |
| 4449 | Hudson | 1,127 |
| 4422 | Charleston | 1,094 |
| 4410 | Bradford | 1,090 |
| 4765 | Patten | 1,030 |
| 4453 | Lagrange | 870 |
| 4939 | Garland | 817 |
| 4455 | Lee | 814 |
| 4487 | Springfield | 812 |
| 4475 | Passadumkeag | 505 |
| 4777 | Stacyville | 427 |
| 4417 | Burlington | 407 |
| 4495 | Winn | 349 |
| 4489 | Stillwater | 327 |
The data shown reflect ZCTAs from the US Census. As of 2024, there are 41 ZCTAs in Penobscot County, Maine (US Census).