The blue area is Maryland; the red area is area codes 240 and 301

North American area codes 240 and 301 are State of Maryland telephone area codes which serve Maryland's portion of the Greater Washington, D.C. metro area, portions of southern Maryland, and all points northwest of Washington. This includes the communities of Cumberland, Frederick, Hagerstown, and Gaithersburg. Area code 301 was one of the original area codes established in 1947, and was the exclusive area code for the entire state of Maryland until it was split to form 410 on October 6, 1991. The overlay area code, 240, was introduced on June 1, 1997.

Counties served by these area codes include:

• Allegany
• Charles
• Frederick
• Garrett
• Howard
• Montgomery
• Prince George's
• St. Mary's
• Washington

Local calls require 10-digit dialing (area code + number, leading "1" is not required).

Area code 227 is scheduled to be overlayed with 301/240 some time in the near future to provide additional assignable numbers.

[edit] External links

• NANPA Area Code Map of Maryland
• List of exchanges from AreaCodeDownload.com, 301 Area Code
• List of exchanges from AreaCodeDownload.com, 240 Area Code