South region · Eastern Time
Maryland Area Codes
All 5 area codes serving Maryland, the cities each one covers, and which are overlays. Maryland is served by 5 area codes in the Eastern Time zone.
Last updated June 5, 2026
Full list
Every Maryland area code
Maryland is served by 5 area codes in the Eastern Time zone. 4 of these are overlay codes layered over busy metros; the rest are geographic codes.
| Code | Main city | Type | Status |
|---|---|---|---|
| 240 | Frederick | Overlay | In service |
| 301 | Frederick | Geographic | In service |
| 410 | Baltimore | Overlay | In service |
| 443 | Baltimore | Overlay | In service |
| 667 | Baltimore | Overlay | In service |
Area codes and dialing in Maryland
Maryland's 5 area codes mix older geographic codes with newer overlays. The busiest metros — around Baltimore, Frederick — carry the most numbers and rely on overlays, which is why 10-digit dialing is required there. Quieter parts of the state may still use a single code. The original code in the Maryland list is 240 (Frederick).
Whenever a Maryland region runs low on numbers, a new overlay is added on top rather than splitting the map, so existing customers keep their numbers. See 10-digit dialing for what that means in practice, or the newest area codes for upcoming changes.
Cities with multiple area codes
These Maryland metros are served by an overlay of two or more codes, so 10-digit dialing applies: Baltimore · Frederick.
Browse Maryland another way
Explore by South region, by time zone, or jump to the city index. You can also see the complete numeric list of every US area code.
Quick answers
Maryland area code FAQ
How many area codes does Maryland have?
Maryland currently has 5 area codes: 240, 301, 410, 443, 667.
What is the main area code for Maryland?
The busiest metro in Maryland is served by the 240 code. Major cities include Baltimore, Frederick.
Does Maryland require 10-digit dialing?
Yes, in its overlay metros you must dial all 10 digits. Ten-digit dialing is the national standard.