List of original NANP area codes

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This is the list of original North American Numbering Plan area codes of 86 plan areas as defined by AT&T in 1947.

In preparation for direct distance dialing, AT&T and the Bell System developed the North American Numbering Plan in the 1940s. The plan divided the United States and Canada into numbering plan areas (NPAs) and assigned a three-digit dialing prefix to each. Over the course of the decade following introduction of these routing codes, local subscriber numbers were standardized to seven digits. This included a three-digit central office prefix, dialed as the first two letters of the local central office name and one digit, and the four-digit subscriber station number.[1]

The first digit of the area code was never 0 or 1, as a single leading pulse (1) was ignored by most switching equipment, and 0 could be confused with requests for an operator or the long-distance desk.[2] The original numbering plan defined the second digit of all area codes as either 0 or 1, to distinguish them from the central office codes, which always used a letter in the middle position, as letters were mapped on the dial only to digits 2 through 9. Area codes with the middle digit 0 were assigned to numbering plan areas that covered an entire state or province, while jurisdictions with multiple plan areas received area codes having 1 as the second digit.[3]

No codes of the form N00, N10 or N11 occurred in the original area code allocation, where N is 2 through 9. The series N00 was used for non-geographic numbers, starting with intrastate toll-free 800-numbers in 1966.[4] N10 numbers were originally teletypewriter exchanges and N11 remains reserved for information and emergency numbers. No codes were originally assigned to Alaska, Hawaii, or Puerto Rico, as neither were US states at the time.[5]

Initially, the numbering plan area codes were used in Nationwide Operator Toll Dialing by long-distance operators for placing trunk calls.[6] Preparations proceeded for end-customer direct distance dialing (DDD) and while the first customer-dialed call using an area code was placed on November 10, 1951, from Englewood, New Jersey, to Alameda, California.[7] it took until the 1960s until direct distance dialing was commonplace in most cities.

Area code Assigned state, province, or region
201 New Jersey
202 District of Columbia
203 Connecticut
204 Manitoba
205 Alabama
206 Washington
207 Maine
208 Idaho
212 New York (New York City)
213 California (Southern California, including Los Angeles)
214 Texas (northeastern Texas, including Dallas/Fort Worth)
215 Pennsylvania (southeastern Pennsylvania, including Philadelphia)
216 Ohio (northeastern Ohio, including Cleveland)
217 Illinois (central)
218 Minnesota (except southeastern part of state)
301 Maryland
302 Delaware
303 Colorado
304 West Virginia
305 Florida
306 Saskatchewan
307 Wyoming
312 Illinois (Chicago metropolitan area)
313 Michigan (southeast Michigan, including Detroit)
314 Missouri (eastern Missouri, including St. Louis)
315 New York (central upstate New York, including Syracuse)
316 Kansas (southern half of Kansas)
317 Indiana (northern two-thirds of Indiana, including Indianapolis)
319 Iowa (eastern third of Iowa)
401 Rhode Island
402 Nebraska
403 Alberta
404 Georgia
405 Oklahoma
406 Montana
412 Pennsylvania (western Pennsylvania, including Pittsburgh)
413 Massachusetts (western Massachusetts, including Springfield)
414 Wisconsin (southern and northeastern Wisconsin, including Milwaukee)
415 California (northern/central California, including San Francisco and Sacramento)
416 Ontario (southern portion from Cobourg to Kitchener, including Toronto)
418 Quebec (eastern half of Quebec, including Québec City)
419 Ohio (northwest Ohio, including Toledo)
501 Arkansas
502 Kentucky
503 Oregon
504 Louisiana
505 New Mexico
512 Texas (central and southern Texas, including Austin and San Antonio)
513 Ohio (southwest Ohio, including Cincinnati)
514 Quebec (western half of Quebec, including Montreal)
515 Iowa (central Iowa, including Des Moines)
517 Michigan (south-central portion of Lower Peninsula, including Lansing)
518 New York (northeastern New York, including Albany)
601 Mississippi
602 Arizona
603 New Hampshire
604 British Columbia
605 South Dakota
612 Minnesota (southeastern portion, including Minneapolis)
613 Ontario (all except a southern portion covering Oshawa-Toronto-Kitchener)
614 Ohio (southeast, including Columbus)
616 Michigan (Grand Rapids, Upper Peninsula, western portion of Lower Peninsula)
617 Massachusetts (eastern Massachusetts, including Boston)
618 Illinois (southern Illinois, including East St. Louis and Carbondale)
701 North Dakota
702 Nevada
703 Virginia
704 North Carolina
712 Iowa (western third, including Sioux City)
713 Texas (southeastern Texas, including Houston)
715 Wisconsin (northern Wisconsin)
716 New York (western New York, including Buffalo and Rochester)
717 Pennsylvania (eastern half, except for the Delaware and Lehigh Valleys)
801 Utah
802 Vermont
803 South Carolina
812 Indiana (southern Indiana)
814 Pennsylvania (northwestern and central Pennsylvania)
815 Illinois (northern Illinois, except Chicago and Quad Cities)
816 Missouri (northwestern Missouri, including Kansas City)
901 Tennessee
902 Nova Scotia, Prince Edward Island, New Brunswick
913 Kansas (northern half of Kansas)
914 New York (southern New York, including Long Island, but excluding New York City)
915 Texas (western Texas, including El Paso)
916 California (northern California, but not including Sacramento)

See also[edit]

References[edit]

  1. ^ AT&T (1955), Notes on Nationwide Dialing, pp.3
  2. ^ AT&T (1955), Notes on Nationwide Dialing, pp.3
  3. ^ http://www.theatlantic.com/technology/archive/2014/02/our-numbered-days-the-evolution-of-the-area-code/283803/
  4. ^ http://www.atlantatelephonehistory.info/part4.html
  5. ^ http://www.lincmad.com/map1947.html
  6. ^ Ralph Mabbs, Nation-Wide Operator Toll Dialing—the Coming Way, Bell Telephone Magazine 1947 p.180
  7. ^ First direct-dial call