ZIP Codes in Glen Arm, MD
Glen Arm uses 1 ZIP code, all in Baltimore County. Pick one below for details, or look up the full nine-digit ZIP+4 for a specific street address.
All 1 Glen Arm ZIP codes
| ZIP | Type | County | Population |
|---|---|---|---|
| 21057 | standard | Baltimore | 4,386 |
Finding a ZIP+4 in Glen Arm
Knowing which of these 1 ZIP codes covers an address only gets you partway. The four-digit extension identifies the specific delivery point — typically one side of one block. Two houses facing each other on the same Glen Arm street almost always have different ZIP+4 codes even though they share all five leading digits.
Appending ZIP+4 to a mailing list?
Upload a CSV of Glen Arm addresses and download it complete.