Area codes 240 and 301
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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.
The main area code, 301, was one of the original area codes
established in 1947. It originally served the entire state, even though it
is home to two very large metropolitan areas, Washington and
Baltimore. The North American Numbering Plan Administrator wanted
to keep the number of "clicks" to a minimum for densely populated
areas given the rotary dialing technology in use at the time, so it gave
Maryland an area code with four clicks.
Maryland consists of the red and blue areas. The red area
Despite the presence of the Baltimore-Washington area, 301 indicates area codes 240 and 301. This map is clickable;
remained the exclusive area code for Maryland for over 40 years. By click on any neighboring area code to go to the page for
the end of the 1980s, however, the Baltimore-Washington corridor's
rapid growth made it obvious that Maryland needed a second area
code. The supply of numbers was further limited by the fact that the entire Washington metropolitan area is a single LATA
spilling into Virginia. Finally, Baltimore and the Eastern Shore were split off as area code 410 on October 6, 1991. The split
largely followed metro area lines. However, Howard County, which is reckoned as part of the Baltimore area, stayed in 301.
This was intended as a long-term solution, but within four years 301 was close to exhaustion due to the proliferation of cell
phones and pagers, especially in the Washington suburbs. To solve this problem, the overlay area code 240 was introduced
on June 1, 1997.
Counties served by these area codes include:
Local calls require 10-digit dialing (area code + number, leading "1" is not required).
Area code 227 is scheduled to be overlaid with 301/240 some time in the longer term to provide additional assignable
numbers, although the current area codes are not expected to exhaust before 2020.
NANPA Area Code Map of Maryland
List of exchanges from AreaCodeDownload.com, 301 Area Code
List of exchanges from AreaCodeDownload.com, 240 Area Code
Maryland area codes: 240, 301, 410, 443
North: 717, 724/878, 814
West: 202, 304/681, 540, 571/703 area codes 301/240 East: 410/443
South: 804, 304/681
District of Columbia area codes: 202
Pennsylvania area codes: 215, 267, 412, 484, 570, 610, 717, 724, 814, 878
Virginia area codes: 276, 434, 540, 571, 703, 757, 804
West Virginia area codes: 304, 681
via Area codes 240 and 301