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Area codes 301, 240, and 227

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This is an old revision of this page, as edited by Klparrot (talk | contribs) at 20:24, 14 October 2012 (correct bad information about number of rotary clicks and explained justification for longer-clicked code). The present address (URL) is a permanent link to this revision, which may differ significantly from the current revision.

area codes 240 and 301Area code 215Area code 856Area code 484Area code 717Area code 814Area code 724Area code 202Area code 571Area code 757Area code 302Area code 410Area code 304Area code 804Area code 434Area code 540
Maryland consists of the red and blue areas. The red area indicates area codes 240 and 301. This map is clickable; click on any neighboring area code to go to the page for that code.


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, Baltimore and the suburbs of Washington, D.C.. 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. Though codes as short as 5 clicks were possible for area codes covering just a city or portion of a state, area codes covering an entire state always had 0 as the middle digit, for a minimum of 13 clicks. Maryland was assigned one of the shortest full-state area codes, with 14 clicks (3+10+1).

Despite the presence of the Baltimore-Washington area, 301 remained the exclusive area code for Maryland for over 40 years. By 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.


Maryland area codes: 301/240/227, 410/443/667
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: 202/771
Pennsylvania area codes: 215/267/445, 412, 570/272, 610/484/835, 717/223, 724, 814/582, 878
Virginia area codes: 276, 434, 540/826, 703/571, 757/948, 804/686
West Virginia area codes: 304/681
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