Maryland Area Codes
5 area codes in Maryland, United States. Country code: +1. Find area codes by city and region.
All Maryland Area Codes
| Area Code | Major Cities | Region |
|---|---|---|
| 240 | Suburban MD (overlay) | DC Metro |
| 301 | Silver Spring, Rockville | DC Metro |
| 410 | Baltimore, Annapolis | Central |
| 443 | Baltimore (overlay) | Central |
| 667 | Baltimore (overlay) | Central |
About Maryland Area Codes
Maryland uses 5 area codes under the North American Numbering Plan (NANP), serving Annapolis, Baltimore, Rockville, Silver Spring. Each code follows the 3-digit format and covers a defined geographic region within the state.
Overlay Codes in Maryland
Maryland has adopted 3 overlay code(s): 240, 443, 667. An overlay assigns a new area code to the same geographic region as an existing code, so both codes serve the same area. When overlay codes are active, callers must dial all 10 digits (area code + number) even for local calls within the same region.
Major Cities and Their Area Codes
Find which area code serves each major city in Maryland.
| City / Community | Area Code(s) |
|---|---|
| Annapolis | 410 |
| Baltimore | 410 |
| Rockville | 301 |
| Silver Spring | 301 |
How to Call Maryland
Within the US: dial 1 + area code + 7-digit number (10-digit dialing applies where overlays are active).
From Canada or the Caribbean: the same NANP format applies — 1 + area code + number.
From abroad: dial your country's exit code (011 from the US, 00 from most countries, or + on mobile), then 1, then the Maryland area code and number.
Example (from the UK): 00 1 240 XXX XXXX
Data source: North American Numbering Plan Administration (NANPA), ITU-T E.164. Area code assignments change with new overlays — verify with your carrier before dialing. NANPA