Maryland comprises the red and blue area of the map; the red area is covered by area codes 410 and 443

Area codes 410 and 443 are telephone area codes serving the eastern half of the U.S. state of Maryland. The 410 area code is the main area code, while the 443 code is an overlay code, used mainly with cell phones. Before these area codes were created, all of Maryland was served by area code 301. In 1991, the Maryland government came up with a plan to add a second area code, the 410 code, to the state. They eventually decided that the Baltimore metropolitan area and the Eastern Shore area would get the new area code, and the western and southern parts of Maryland and the Washington, D.C. suburbs would remain with the 301 area code. The 443 overlay code took effect on July 1, 1997.

The counties served by this area code include:

In the Baltimore metropolitan area: The independent city of Baltimore, as well as Anne Arundel, Baltimore, Calvert, Carroll, Harford, and Howard counties.

On the Eastern Shore: Caroline, Cecil, Dorchester, Kent, Queen Anne's, Somerset, Talbot, Wicomico, and Worcester counties.

[edit] See also

• NANPA Area Code Map of Maryland
• List of exchanges from AreaCodeDownload.com, 410 Area Code
• List of exchanges from AreaCodeDownload.com, 443 Area Code