Maryland Area Codes

About Area Codes in Maryland

Maryland (MD) is the The Old Line State, located in the South region of the United States. With a 2023 population of 6,180,253 residents, Maryland is served by 5 active area codes. The state capital is Annapolis and the largest city is Baltimore.Maryland's official motto is "Fatti maschii, parole femine."

Area code assignments in Maryland follow the North American Numbering Plan (NANP), which has been in effect since 1947. As the state's population and demand for phone numbers grew — driven by the rise of cell phones, fax machines, pagers, and VoIP lines — regulators either split existing area codes geographically or added overlay codes that share the same territory. That's why Maryland now has 5 codes: 240, 301, 410, 443, 667.

When you receive a call from a Maryland number, the area code tells you only where the number was originally assigned. Because of Local Number Portability (LNP), which took effect in 2003, callers can keep their phone numbers even when moving across state lines. So while a 240 number was once assigned in Maryland, the person calling you could be anywhere in the US today.

Time zones in Maryland

Maryland observes the Eastern time zone. Daylight Saving Time is observed from the second Sunday in March through the first Sunday in November, when clocks shift forward by one hour. When you call a Maryland number from outside the state, double-check the local time above each area code detail page to avoid calling at unreasonable hours.

Phone number format in Maryland

All Maryland phone numbers follow the standard 10-digit NANP format: (NPA) NXX-XXXX. For local calls within Maryland, you typically need to dial the full 10-digit number — even for calls within the same area code — because of mandatory 10-digit dialing imposed by the FCC for areas with overlay codes (most of Maryland's territory). For long-distance calls within the NANP, dial 1 + area code + 7-digit number.

Frequently asked questions about Maryland area codes

How many area codes does Maryland have?

Maryland currently has 5 active area codes: 240, 301, 410, 443, 667.

What is Maryland's original area code?

The oldest area code(s) in Maryland were assigned in 1947 as part of the original 86 NANP codes. These legacy codes typically covered the entire state at first, then were split as demand grew.

What time zone is Maryland in?

Maryland is in the Eastern time zone.

Will Maryland get more area codes?

As Maryland's population and number demand grow, NANPA may assign additional overlay codes. When the current codes run out of available prefixes, regulators announce public hearings and propose new codes. The AreaCodeCentral team tracks these announcements and updates the directory within 24 hours of any new code activation.