20 zips
| Zip Code | City | Population ↓ |
|---|---|---|
| 21014 | Bel Air | 37,976 |
| 21009 | Abingdon | 33,444 |
| 21015 | Bel Air | 30,451 |
| 21001 | Aberdeen | 26,121 |
| 21040 | Edgewood | 25,290 |
| 21078 | Havre De Grace | 20,002 |
| 21050 | Forest Hill | 17,848 |
| 21085 | Joppa | 16,511 |
| 21047 | Fallston | 13,540 |
| 21084 | Jarrettsville | 7,488 |
| 21154 | Street | 7,187 |
| 21017 | Belcamp | 6,404 |
| 21161 | White Hall | 5,288 |
| 21132 | Pylesville | 2,904 |
| 21028 | Churchville | 2,872 |
| 21034 | Darlington | 2,802 |
| 21160 | Whiteford | 2,543 |
| 21005 | Aberdeen Proving Ground | 2,354 |
| 21010 | Gunpowder | 216 |
| 21130 | Perryman | 75 |
The data shown reflect ZCTAs from the US Census. As of 2024, there are 20 ZCTAs in Harford County, Maryland (US Census).