410 area code — Baltimore, MD geographic
The 410 area code covers Baltimore, Maryland, Eastern time zone, and dates back to October 6, 1991. Together with 443, 667 it forms the 410/443/667 overlay. Because of number portability and VoIP, the area code tells you where the number was issued, not where the caller is right now.
NANPA lists 783 active NXX prefixes in 410, assigned to 27 carriers. 377 of those prefixes are pooled — shared between carriers in thousands-number blocks. The code spans 102 rate centers (billing localities).
Official projections put exhaust for the 410/443/667 complex at 1Q 2036.
The dialing plan is 10D for home-NPA local calls and 10D across codes.
Worth noting: 410 is covers more rate centers (102) than any other Maryland area code.
Practical takeaway: the 410 label narrows geography to Maryland, the prefix narrows it to a locality, and neither authenticates a caller. Verification means calling back through a number you found yourself.
Its parent code is 301, which it left in 1991. Later relief produced 443 (1997) from its territory.
Largest localities in 410
| Locality (rate center) | Active prefixes | Also served by |
|---|---|---|
| Baltimore | 189 | 301, 443, 667 |
| Towson | 53 | 443, 667 |
| Annapolis | 36 | 443, 667 |
| Catonsville | 35 | 443, 667 |
| Glen Burnie | 29 | 443, 667 |
| Salisbury | 24 | 443, 667 |
| Waterloo 236 | 23 | 443, 667 |
| Elkridge | 20 | 443, 667 |
| Columbia | 20 | 443, 667 |
| Pikesville | 19 | 443, 667 |
FAQ
Will 410 run out of numbers?
NANPA's current forecast projects exhaust in 1Q 2036 — decades of capacity remain.
Why am I getting spam calls from 410 numbers?
Scammers spoof recognizable area codes so calls look local or familiar. A displayed 410 number does not prove the call originated there — see our guide to spotting spoofed calls.
Where is a 410 number from?
410 is assigned to Baltimore and surrounding areas of Maryland in the Eastern time zone. The three digits after the area code (the prefix) narrow it down to a rate center.