18 zips
| Zip Code | City | Population ↓ |
|---|---|---|
| 80501 | Longmont | 43,222 |
| 80503 | Longmont | 36,235 |
| 80027 | Louisville | 34,161 |
| 80026 | Lafayette | 32,675 |
| 80302 | Boulder | 30,569 |
| 80304 | Boulder | 25,617 |
| 80303 | Boulder | 24,865 |
| 80301 | Boulder | 24,593 |
| 80305 | Boulder | 16,280 |
| 80310 | Boulder | 7,597 |
| 80540 | Lyons | 4,637 |
| 80466 | Nederland | 3,442 |
| 80481 | Ward | 532 |
| 80510 | Allenspark | 522 |
| 80455 | Jamestown | 402 |
| 80025 | Eldorado Springs | 45 |
| 80471 | Pinecliffe | 0 |
| 80544 | Niwot | 0 |
The data shown reflect ZCTAs from the US Census. As of 2024, there are 18 ZCTAs in Boulder County, Colorado (US Census).