190:. From 1947 to 1990, it was possible to dial any other telephone number in the metro area as a local call with only seven digits, not using an area code, irrespective of the home area code. The entire metro area was also reachable via long-distance services by dialing area code 202, for which purpose AT&T had established cross-referenced operator routing codes for all affected central offices. For example, if 202-574 numbers were in use in the District or 703-574 numbers were in use in Northern Virginia, the corresponding 301-574 numbering block could only be assigned in areas considered a safe distance away from the capital, such as the
31:
214:) cooperated in ending code protection for the Washington area on October 1, 1990. Ten-digit dialing was now required for all local calls between Maryland, the District of Columbia, and Virginia. Area code 202 was no longer usable for suburban points. Local calls within Maryland did not require the area code. Permissive dialing using the old dialing procedures continued from April 1 through October 1, 1990.
48:
45:
286:
A September 2022 study projected that the 301/240 numbering plan area (NPA) would suffer central office code exhausted between April and June 2023. Area code 227 was already approved as an all-services distributed overlay since
January 3, 2001 for the 301/240 NPA. The new area code went into service
256:
When an area code is split, the largest city, in this case
Baltimore, in the old numbering plan area typically retains the existing area code to minimize expense for changing telephone numbers. However, Bell Atlantic wanted to spare the large number of federal agencies on the Maryland side of the
265:
Although the area code split was intended as a long-term solution, within four years 301 was close to exhaustion due to the proliferation of cell phones and pagers, especially in the
Washington suburbs. In relief action, area code 240 was introduced on June 1, 1997, to form the state's first
257:
Washington area from the expense and disruption of a new area code. While
Maryland would have likely needed another area code due to the growth of the Baltimore-Washington corridor, it is likely that a split would have been delayed had more 301 numbers been available for use in Baltimore.
44:
206:. The only unassigned prefixes were unavailable due to the central office code protection that maintained seven-digit dialing in the metro-area. Assignment of these prefixes would require dialing an area code. The three local operating companies of the
36:
41:
46:
37:
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In Howard County, Mount Airy exchange 829 and Laurel exchanges 210, 317, 490, 497, 598, 604, 725, and 776 remained area code 301. The rest of the county was assigned area code 410.
38:
43:
253:, which is often recognized as part of the Baltimore metropolitan area, a small portion of the county remained in 301, while the rest of the county was reassigned to 410.
42:
226:, By the end of the 1980s, it became apparent that terminating central office code protection in the Washington area could not free up sufficient resources north of the
35:
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on June 14, 2023, at which time activation of new central office codes could begin, once all assignable central office codes in 240/301 had been exhausted.
223:
40:
927:
164:
39:
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for the 301 territory. On June 14, 2023, a third overlay code, 227, was added to provide more central office prefixes for new telephone numbers.
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By the end of the 1980s, the
Washington metropolitan area was running out of assignable prefixes for new central offices on both sides of the
139:
Area code 301 was the first area code for all of
Maryland, from 1947, when the area code system was created, until 1991, when everything from
274:. It was decided to create an overlay rather than split the region into two numbering plan areas to avoid assigning a new area code to 1.2
312:
160:
316:
932:
453:
Jordan, Mary; Quimpo, Margie G. (September 23, 1990). "Territorial
Telephones; On Oct. 1, Local Calls Will Get Complicated".
424:
668:
336:
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million existing telephone numbers. At the time, it was predicted that it would take until 2008 to exhaust area code 240.
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852:
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728:
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427:, meaning that no central office code in the metro area could exist in more than a single central office.
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270:. Overlays were a new concept at the time, and met with some resistance due to the requirement for
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Maryland consists of the red and blue areas. The red area has area codes 227, 240 and 301.
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Local calls require ten-digit dialing (area code + number, leading "1" is not required).
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exchange 829 remained area code 301. The rest of the county was assigned area code 410.
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exchange 952 remained area code 301. The rest of the county was assigned area code 410.
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largely followed metropolitan area lines. There were a few exceptions, such as in
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645:"Planning Letter PL-603: NPA 227 and 240/301 All-Services Overlay (Maryland)"
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182:, and also extends into the suburban area in southern Maryland with 301 and
140:
77:. The numbering plan area (NPA) comprises Maryland's portion of the Greater
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875:
720:
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211:
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is part of a local calling area which is centered on the
District's
718:
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exchanges 210, 317, 490, 497, 498, 596, 604, 725, and 778 and
625:. North American Numbering Plan Administrator. April 21, 2021
171:
in 1947. The area code served the entire state of
Maryland.
27:
North
American telephone area codes in Western Maryland, U.S.
295:
The numbering plan area 301/240/227 include the counties of
245:
on November 1, 1991, to form a new numbering plan area. The
609:. The Gettysburg Times (Gettysburg, Pennsylvania). p. A3.
713:
708:
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Four counties were split between area code 301 and 410.
210:(C&P Telephone, later part of Bell Atlantic and now
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Most of Frederick County remained area code 301. Only
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to stave off the immediate need for a new area code.
423:(April 1974) This was implemented via a system of
938:Telecommunications-related introductions in 1947
494:New Area Code 410 Starts Nov. 1 in Half of State
438:Area Codes Needed to Call Between Md., D.C., Va.
33:
592:(Salisbury, Maryland). January 23, 1997. p. 4.
575:. The Star-Democrat (Easton, Maryland). p. A1.
466:NANPA Bellcore Information Letter IL-90/04-003
8:
547:North American Numbering Plan Administration
518:North American Numbering Plan Administration
397:exchange 635 were assigned area code 410.
669:New Area Code Coming to Parts of Maryland
167:(AT&T) established a new, nationwide
147:. In 1997, area code 240 was added as an
361:
359:
357:
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208:Chesapeake and Potomac Telephone Company
165:American Telephone and Telegraph Company
569:Maryland Gets Read for 10-digit Dialing
412:
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686:"New area code for eastern Maryland".
620:"2022-1 NRUF and NPA Exhaust Analysis"
567:Yates, Jennifer C. (April 22, 1997). "
241:were reassigned from area code 301 to
224:Baltimore–Washington metropolitan area
7:
475:Muth, Charlie (November 17, 1990). "
492:Hetrich, Ross (October 25, 1991). "
92:. This includes the communities of
69:(NANP) for the western part of the
667:Duffy, Ken (September 28, 2022). "
603:10-digit Dialing Comes to Maryland
222:Despite the overall growth of the
161:original North American area codes
25:
704:NANPA area code map of Maryland
601:Pemberton, Mary (May 2, 1997). "
421:Distance Dialing Reference Guide
928:Area codes in the United States
483:(Salisbury, Maryland). p. 1, 4.
540:"Bellcore Letter IL 96/06-009"
511:"Bellcore Letter IL-90/12-049"
425:central office code protection
331:, and slivers of southwestern
1:
159:Area code 301 was one of the
67:North American Numbering Plan
176:Washington metropolitan area
56:Area codes 301, 240, and 227
954:
690:. November 1, 1991. p. 1A.
586:Ready for 10-digit Stroll?
477:Shore to Get New Area Code
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714:240 Area Code in Maryland
709:301 Area Code in Maryland
498:The Baltimore Evening Sun
444:. October 1, 1990. p. 2B.
192:Eastern Shore of Maryland
368:In Anne Arundel County,
169:telephone numbering plan
933:Area codes in Maryland
233:In mitigation action,
143:eastward split off as
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18:Area codes 301 and 240
419:AT&T Long Lines,
50:
826:District of Columbia
731:
650:. NANPA. 2022-09-27
455:The Washington Post
337:Anne Arundel County
88:, along with rural
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379:In Carroll County
323:counties, most of
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916:
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688:The Baltimore Sun
442:The Baltimore Sun
393:exchange 775 and
272:ten-digit dialing
198:Ten-digit dialing
184:Northern Virginia
149:overlay area code
86:southern Maryland
16:(Redirected from
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79:Washington, D.C.
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243:area code 410
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239:Eastern Shore
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228:Potomac River
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204:Potomac River
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188:area code 703
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909:area codes:
878:area codes:
839:area codes:
837:Pennsylvania
828:area codes:
808:
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789:
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766:
737:
724:
723:area codes:
687:
682:
672:
663:
652:. Retrieved
639:
627:. Retrieved
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551:. Retrieved
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522:. Retrieved
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391:Union Bridge
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335:and western
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291:Service area
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174:Much of the
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138:
106:Gaithersburg
55:
54:
853:610/484/835
841:215/267/445
800:410/443/667
790:301/240/227
788:area codes
729:410/443/667
725:301/240/227
395:New Windsor
282:227-overlay
261:240-overlay
922:Categories
654:2023-05-27
407:References
381:Mount Airy
327:, western
321:Washington
317:St. Mary's
309:Montgomery
114:Germantown
102:Hagerstown
94:Cumberland
82:metro area
71:U.S. state
63:area codes
549:. Neustar
520:. Neustar
500:. p. C12.
235:Baltimore
218:410-split
163:when the
141:Baltimore
122:Rockville
98:Frederick
60:telephone
876:Virginia
721:Maryland
629:July 15,
524:June 21,
374:Marlboro
297:Allegany
237:and the
126:Landover
118:Bethesda
75:Maryland
911:304/681
900:804/686
896:757/948
892:703/571
888:540/826
865:814/582
857:717/223
849:570/272
830:202/771
817:304/681
813:804/686
783:703/571
779:540/826
775:304/681
771:202/771
758:814/582
742:717/223
553:21 June
457:. p. 1.
305:Garrett
301:Charles
268:overlay
212:Verizon
155:History
134:Waldorf
110:Potomac
65:in the
370:Laurel
276:
132:, and
809:South
738:North
648:(PDF)
623:(PDF)
543:(PDF)
514:(PDF)
346:Notes
186:with
796:East
767:West
674:WBAL
631:2021
555:2013
526:2013
319:and
58:are
884:434
880:276
869:878
861:724
845:412
754:878
750:724
746:412
671:".
605:".
588:".
571:".
496:".
479:".
73:of
924::
898:,
894:,
890:,
886:,
882:,
867:,
863:,
859:,
855:,
851:,
847:,
843:,
815:,
811::
798::
781:,
777:,
773:,
769::
756:,
744:,
740::
727:,
545:.
516:.
440:"
354:^
339:.
315:,
311:,
307:,
303:,
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194:.
136:.
128:,
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112:,
108:,
104:,
100:,
96:,
752:/
748:/
677:.
657:.
633:.
584:"
557:.
528:.
436:"
20:)
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