20 zips
| Zip Code | City | Population ↓ |
|---|---|---|
| 21014 | Bel Air | 37,097 |
| 21009 | Abingdon | 32,565 |
| 21015 | Bel Air | 30,485 |
| 21001 | Aberdeen | 25,908 |
| 21040 | Edgewood | 25,110 |
| 21078 | Havre De Grace | 19,820 |
| 21050 | Forest Hill | 18,076 |
| 21085 | Joppa | 16,590 |
| 21047 | Fallston | 13,419 |
| 21084 | Jarrettsville | 7,366 |
| 21154 | Street | 7,059 |
| 21017 | Belcamp | 6,177 |
| 21161 | White Hall | 5,625 |
| 21132 | Pylesville | 3,110 |
| 21028 | Churchville | 2,974 |
| 21034 | Darlington | 2,958 |
| 21160 | Whiteford | 2,716 |
| 21005 | Aberdeen Proving Ground | 2,703 |
| 21010 | Gunpowder | 216 |
| 21130 | Perryman | 21 |
The data shown reflect ZCTAs from the US Census. As of 2024, there are 20 ZCTAs in Harford County, Maryland (US Census).