| Localité | Code postal |
|---|---|
| Aberdeen, Harford | 21001 |
| Aberdeen Proving Ground, Harford | 21005 |
| Abingdon, Harford | 21009 |
| Bel Air, Harford | 21014, 21015 |
| Belcamp, Harford | 21017 |
| Benson, Harford | 21018 |
| Cardiff, Harford | 21160 |
| Churchville, Harford | 21028 |
| Darlington, Harford | 21034 |
| Edgewood, Harford | 21040 |
| Edgewood Arsenal, Harford | 21010 |
| Fallston, Harford | 21047 |
| Forest Hill, Harford | 21050 |
| Gunpowder, Harford | 21010 |
| Havre De Grace, Harford | 21078 |
| Jarrettsville, Harford | 21084 |
| Joppa, Harford | 21085 |
| Joppatown, Harford | 21085 |
| Joppatowne, Harford | 21085 |
| Norrisville, Harford | 21161 |
| Perryman, Harford | 21130 |
| Pylesville, Harford | 21132 |
| Riverside, Harford | 21017 |
| Street, Harford | 21154 |
| White Hall, Harford | 21161 |
| Whiteford, Harford | 21160 |