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 exchange name and one digit, and the four-digit subscriber line number.[citation needed]

The original numbering plan defined the second digit of all area codes as either 0 or 1, to distinguish them from the local telephone exchange prefixes, which were assigned digits 2 through 9 in the second position. Area codes with a middle digit 0 (zero, ten dial pulses) were assigned to plan areas that covered an entire state or province, while jurisdictions with multiple plan areas received area codes having 1 (one, a single pulse) in the second digit.[1] This permitted long distance calls to be dialed within the same area code as a seven digit subscriber number without the area code.[citation needed]

The most prominent, frequently called population centers were assigned digit sequences with the shortest dial time on rotary dial telephones.[2] The dialing time was determined by the amount of rotation of the dial that was needed to dial each digit. Digits 1 to 9 produced the corresponding number of pulses, and 0 resulted in ten pulses. For example, New York City was assigned area code 212 (five pulses), Los Angeles 213 (six pulses), Chicago 312 (six pulses), and Detroit 313 (seven pulses), while the area code with the lowest number, 201, produced 13 pulses.[citation needed] Adjacent areas were generally assigned codes that were not easily confused with one another, to minimize wrong numbers.[citation needed]

No codes of the form N00, N10 or N11 occur in the original set, with N=2, 3, ..., 9. The series N00 was used for non-geographic numbers, starting with intrastate toll-free 800-numbers in 1966.[3] N10 numbers were originally teletypewriter exchanges and N11 remains reserved for information and emergency numbers. No codes were originally assigned to Alaska and Hawaii, as neither were US states at the time, or Puerto Rico.[4]

Initially, the codes were used by long-distance operators for trunk calls while preparations proceeded for end-customer direct distance dialing. The first customer-dialed call using an area code was placed on November 10, 1951, from Englewood, New Jersey, to Alameda, California.[5] Direct distance dialing was gradually implemented throughout the continent. By the mid-1960s, direct distance dialing was commonplace in large cities.[citation needed]

Original area codes[edit]

Pulse counts for original area codes[edit]

Pulse Count Area Code Area Description
5 212 New York (New York City)
6 213 California (Southern California, including Los Angeles)
6 312 Illinois (Chicago metropolitan area)
7 214 Texas (northeastern Texas, including Dallas/Fort Worth)
7 313 Michigan (southeast Michigan, including Detroit)
7 412 Pennsylvania (western Pennsylvania, including Pittsburgh)
8 215 Pennsylvania (southeastern Pennsylvania, including Philadelphia)
8 314 Missouri (eastern Missouri, including St. Louis)
8 413 Massachusetts (western Massachusetts, including Springfield)
8 512 Texas (central and southern Texas, including Austin and San Antonio)
9 216 Ohio (northeastern Ohio, including Cleveland)
9 315 New York (central upstate New York, including Syracuse)
9 414 Wisconsin (southern and northeastern Wisconsin, including Milwaukee)
9 513 Ohio (southwest Ohio, including Cincinnati)
9 612 Minnesota (southeastern portion, including Minneapolis)
10 217 Illinois (central)
10 316 Kansas (southern half of Kansas)
10 415 California (northern/central California, including San Francisco and Sacramento)
10 514 Quebec (western half of Quebec, including Montreal)
10 613 Ontario (all except a southern portion covering Oshawa-Toronto-Kitchener)
10 712 Iowa (western third, including Sioux City)
11 218 Minnesota (except southeastern part of state)
11 317 Indiana (northern two-thirds of Indiana, including Indianapolis)
11 416 Ontario (southern portion from Cobourg to Kitchener, including Toronto)
11 515 Iowa (central Iowa, including Des Moines)
11 614 Ohio (southeast, including Columbus)
11 713 Texas (southeastern Texas, including Houston)
11 812 Indiana (southern Indiana)
12 319 Iowa (eastern third of Iowa)
12 418 Quebec (eastern half of Quebec, including Québec City)
12 517 Michigan (south-central portion of Lower Peninsula, including Lansing)
12 616 Michigan (Grand Rapids, Upper Peninsula, western portion of Lower Peninsula)
12 715 Wisconsin (northern Wisconsin)
12 814 Pennsylvania (northwestern and central Pennsylvania)
13 201 New Jersey
13 419 Ohio (northwest Ohio, including Toledo)
13 518 New York (northeastern New York, including Albany)
13 617 Massachusetts (eastern Massachusetts, including Boston)
13 716 New York (western New York, including Buffalo and Rochester)
13 815 Illinois (northern Illinois, except Chicago and Quad Cities)
13 913 Kansas (northern half of Kansas)
14 202 District of Columbia
14 301 Maryland
14 618 Illinois (southern Illinois, including East St. Louis and Carbondale)
14 717 Pennsylvania (eastern half, except for the Delaware and Lehigh Valleys)
14 816 Missouri (northwestern Missouri, including Kansas City)
14 914 New York (southern New York, including Long Island, excluding New York City)
15 203 Connecticut
15 302 Delaware
15 401 Rhode Island
15 915 Texas (western Texas, including El Paso)
16 204 Manitoba
16 303 Colorado
16 402 Nebraska
16 501 Arkansas
16 916 California (northern California, excluding Sacramento)
17 205 Alabama
17 304 West Virginia
17 403 Alberta
17 502 Kentucky
17 601 Mississippi
18 206 Washington
18 305 Florida
18 404 Georgia
18 503 Oregon
18 602 Arizona
18 701 North Dakota
19 207 Maine
19 306 Saskatchewan
19 405 Oklahoma
19 504 Louisiana
19 603 New Hampshire
19 702 Nevada
19 801 Utah
20 208 Idaho
20 307 Wyoming
20 406 Montana
20 505 New Mexico
20 604 British Columbia
20 703 Virginia
20 802 Vermont
20 901 Tennessee
21 605 South Dakota
21 704 North Carolina
21 803 South Carolina
21 902 Nova Scotia, Prince Edward Island, New Brunswick

See also[edit]