ZIP Codes in Columbia, MD
Columbia uses 3 ZIP codes, all in Howard County. Pick one below for details, or look up the full nine-digit ZIP+4 for a specific street address.
All 3 Columbia ZIP codes
| ZIP | Type | County | Population |
|---|---|---|---|
| 21044 | standard | Howard | 44,114 |
| 21045 | standard | Howard | 40,034 |
| 21046 | standard | Howard | 15,608 |
Finding a ZIP+4 in Columbia
Knowing which of these 3 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 Columbia 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 Columbia addresses and download it complete.