| 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 |