Maryland ZIP codes
Main ZIP codes for the largest cities in Maryland. Format: 5-digit ZIP code (ZIP+4 optional).
Cities
| City | Code |
|---|---|
| Baltimore | 21201 |
| Annapolis | 21401 |
| Frederick | 21701 |
| Rockville | 20850 |
| Columbia | 21044 |
Large cities have many codes; the code shown is the main/central one. All states & countries →