question: Why were area codes issued such that 512 is Austin, TX; 513 is Cincinnati, OH; 514 is Montreal, QC, and so on? Does it not make sense to go east to west?
comment: The numbers have nothing to do with being sequential, it was never intended as such, it was done for ease of use on rotary phones. Early area codes, such as NYC (212), Los Angeles (213), Chicago (312) were made that because they were large population centers which needed an area code and these were very short and simple to dial on a rotary phone so they were given the "best" (meaning easiest to use) area codes. Note: 1 can't be the first number, and you can't have a number be #11 either, so 2 is the "best" first number, and thus 212 is the simplest area code in this sense There's actually a bit more order and planning here (beyond what I said) but often the #1# scheme is used for a larger city
passages: This similar practice was implemented on a large scale in the metropolitan area of Washington, D.C. and its suburbs in Maryland and Virginia. Until 1991, the entire region was a single local calling area, and it was possible for anyone living in the metro area to dial a number in D.C. or the Maryland and Virginia suburbs with only seven digits. The entire area implemented a system of central office code protection in which no central office code was duplicated in the entire area. Each existing central office code was properly routed with each area code in the region, so that each telephone number in the region could be dialed with any of the regional area codes, giving the appearance of an overlay plan.
   The number allocation problem is not as severe in Montreal as in other areas of Canada, since numbers tend to be used up fairly quickly. However, it was obvious that the Montreal area needed another area code. By this time, overlay area codes had become the preferred relief measure in Canada, as they are an easy workaround for the number allocation problem. Numbering plan area 514 area was overlaid with area code 438 on November 4, 2006, making ten-digit dialing mandatory in the Montreal area.
   BULLET::::- Washington, D.C. (area code 202) to adjacent areas of Maryland (area code 301) and Virginia (area code 703), discontinued on October 1, 1990 to allow assignment of a code in all three area codes.
  
  BULLET::::- Hull from Ottawa before 2006, as every Ottawa-Hull local number originally was reserved in both area code 613 and 819). This was terminated on 21 October 2006 to allow assignment of a code in both 613 and 819, although five central office codes associated with the federal government were protected in 819 to allow dialing without potentially reaching non-government lines.
  
  Section::::Limitations.
   Most area codes of the form N10, originally reserved for AT&T's Teletypewriter eXchange (TWX) service, were transferred to Western Union in 1969 and were freed up for other use in 1981 after conversion to Telex II service was complete. The last of these, 610, was assigned to Canada, but reassigned in 1992. These new area codes, as well as a few other codes used for routing calls to Mexico, were used for telephone area code splits in the late 1980s and early 1990s, as all other area codes under the original plan had been consumed.
   Section::::History.
   Overlays initially were met with resistance, as they resulted in different area codes within the same geographic area. In many cases, such as 847 in northwestern Chicago and 212 in New York City, an overlay was an additional disruption to a community which had already been subject to one or multiple code splits, encountering pushback from state regulators or consumer groups. However, eventually overlay plans were used much more widely in some areas than others. For example, much of Ohio is covered by large overlay complexes, as is northern Georgia. Connecticut, Illinois, Oregon, New Jersey, Massachusetts, Maryland, Pennsylvania, Texas, and, more recently, California have also implemented many overlays. There have been no area code splits since 2007 with area code 575 splitting off 505 in New Mexico, and there are no splits currently proposed (but many overlays). Seven-digit dialing has been broken in most area codes serving major cities; among the few cities where seven-digit dialing is still possible are Detroit, El Paso, Jacksonville, Louisville, Memphis, Milwaukee and Oklahoma City. Even in those cities, seven-digit dialing may only be possible within the area code that serves the city itself, and not outlying areas with different area codes.
   The eastern half of the University of Minnesota, Twin Cities campus, in the St. Paul suburb of Falcon Heights, is a notable exception to the regional numbering plan. Because of an integrated phone system linking both campuses, the Falcon Heights campus remained in 612 after the 1998 split.
  
  The four Twin Cities area codes comprise one of the largest local calling areas in the United States; with a few exceptions, no long-distance charges are applied from one part of the Twin Cities to another. Portions of area codes 320 and 507 are local calls from the Twin Cities as well.
   Many other cities could not yet be included as they did not yet have the necessary toll switching equipment to handle incoming calls automatically on their circuits. Other cities still had either a mixture of local number lengths or were all still six-digit numbers; Montreal, Quebec and Toronto, Ontario in Canada, for example, had a mix of six- and seven-digit numbers from 1951 to 1957, and did not have DDD until 1958. Whitehorse, Yukon had seven-digit numbers from 1965, but the necessary switching equipment was not in place locally until 1972.
  
  Section::::Hardware.
   BULLET::::- Galt (226)-318 362 474 533 616 765 859 894 895, (519)-231 267 543 618 620 621 622 623 624 629 740
  
  BULLET::::- Hespeler (226)-201 218 243 319 341 362 475 566 696 755 860 887 890 924, (519)-212 220 221 222 223 224 230 239 240 241 242 244 248 249 277 651 654 658 700 714 716 841
  
  BULLET::::- Preston (226)-204 473 535 865, (519)-201 219 650 653 920 947
   One anomaly in this area code is that all of it is in Los Angeles County except for the cities of Seal Beach and Los Alamitos, which are in the very northwest corner of the Orange County coastline, portions of the city of La Habra, and the very small and northwest part of the city of Brea in the very northwest corner of inland Orange County. These exceptions could exist because, at the time of 310's creation, Pacific Bell (now AT&T Inc.) was the primary telephone company for most of Southern California, whereas this region's primary telephone company was GTE (now Verizon). In fact, when this region was originally split from the 213 area code to become the 310 area code, Pacific Bell, being the primary local telephone company for this area (and had authority to decide what codes stayed in 213 and which ones moved), chose to move all of GTE's area code 213 exchanges into the 310 area code.
   This part of Washington is not as densely populated as the west, and the great majority of the state's landlines and cell phones are located west of the Cascades. As a result, while western Washington went from one area code to four during the 1990s, 509 has remained unchanged for over 60 years. With western Washington being overlaid with area code 564 in 2017, 509 is the only portion of Washington where seven-digit local dialing is still possible.
   List of Missouri area codes
  
  This is a list of telephone area codes in the state of Missouri.
  
  314: St. Louis and many of its immediate suburbs
  
  417: The southwestern quarter of Missouri, including Springfield, Joplin and Branson
  
  573: Eastern and Southeastern Missouri excluding the St. Louis area but including Jefferson City, Columbia, Rolla, Cape Girardeau and Hannibal
  
  636: Greater St. Louis area, including St. Charles, Jefferson, and western St. Louis counties; forms a ring surrounding the immediate St. Louis area (314)
   BULLET::::- The towns of Seekonk and Rehoboth, Massachusetts share a wire center with East Providence, Rhode Island and code protection was provided in the 401 area code until 2000, allowing Seekonk and Rehoboth subscribers (336-xxxx) to dial calls in the Providence, Rhode Island metro area with 7 digits. This was phased out when New England Telephone began the process of creating an overlay area code for the 508 area code. Ten-digit dialing is now required for calls crossing the area code (and state) boundary.
  
  Section::::Limitations.
   A local call in this scheme, standardized in 1948 for the introduction of direct-dial long distance calling, was originally dialled as a fixed-length seven-digit number and did not require an area code. In some cases, a local call to a number just across an area code boundary could be seven digits if an exchange code protection scheme prevented the same prefixes being assigned to local numbers in the other area code.
   In some areas, decreased code demand and conservation efforts have allowed the introduction of proposed new area codes to be delayed. Area code 564, proposed to overlay the portion of western Washington State currently in area codes 206, 253, 360, and 425 was delayed in 2001 as codes were reclaimed and numbers pooled; it was later reinstated, initially affecting area code 360 and expanding to the other mentioned area codes as needed, with 10-digit dialing set to become mandatory by September 30, 2017. A proposed area code 445 overlaying Philadelphia was scrapped in 2003; it was later reinstated, and is set to go into effect on March 3, 2018. An area code 582 intended to split Pennsylvania's existing area code 814 was abandoned in 2012.
   Additional area code patterns were later assigned for other services; for example, the area codes "N10" were implemented for the Teletypewriter Exchange Service (TWX).
   As a result, the area's low requirements were met by long distance switching as part of southern area codes - 403 in the west and 819 in the east. The Yukon was also covered by 403, not 604, since its lines were handled, prior to Direct Distance Dialing, by operators in Edmonton, Alberta.
  
  The northern British Columbia locations, plus Fort Liard, NT until October 1981, were served by area code 604 so that there would be uniformity of dialing codes within that province. Lower Post, BC, linked with the Watson Lake, YT exchange, was covered by 403 prior to 1979.
   The south and east portions of 310, roughly the Gateway Cities area of Los Angeles County from Long Beach to Whittier and parts of Orange County became area code 562 on January 25, 1997.
   In the original 1947 plan, area codes containing "0" (zero) as a middle digit were only assigned to states that were entirely covered by a single area code. Area code 507, along with area code 606 in Kentucky and area code 607 in New York, were the first area codes with a middle digit of "0" to be assigned to states that were covered by more than one area code.
   On July 29, 2017, ten-digit dialing became mandatory for all local calls in Western Washington, replacing the use of seven-digit dialing. Before then, Seattle had been one of the few major American cities where seven-digit dialing still functioned. Since September 30, 2017, telephone numbers with the area code 564 are issued in the existing number plan area 360. Once other codes in western Washington exhaust, 564 numbers will also be assigned in those areas.
   Central office code protection
  
  In the administration of the North American Numbering Plan, central office code protection was a numbering policy intended to ensure that the same local telephone number was not assigned in both of a pair of adjacent communities on opposite sides of an area code boundary. Its primary purpose was initially to preserve seven-digit dialing of local calls across a common area code boundary in border communities.
   Section::::Prior usage of 510 for TWX.
   By the turn of the millennium, 602 was running out of numbers just four years after all of the state outside of the Valley of the Sun was split off as area code 520. Original plans called for 480 to be an overlay code for the entire Phoenix metro area. However, overlays were a new concept at the time, and met with considerable resistance due to potential geographic ambiguity, as well as the requirement for ten-digit dialing. A three-way geographic split was chosen instead, with 480 assigned to the East Valley.
   Severing the border community from its exhausted home area code using a split plan may prolong the life of a seven-digit exchange code protection scheme if the piece being split off is outside the extended local calling area. Code protection is most often removed entirely in large cities if an overlay plan is implemented, as these plans break the seven-digit dialling that code protection was devised to preserve. The plan also can be expected to break down if new split-plan codes are added within a city the size of Chicago, as the city itself no longer fits into one seven-digit area.
   BULLET::::- Topanga (small portion in the 818 area code)
  
  BULLET::::- Torrance
  
  BULLET::::- West Athens (mostly in the 323 area code)
  
  BULLET::::- West Carson
  
  BULLET::::- West Compton
  
  BULLET::::- West Hollywood (also in the 323 area code)
  
  BULLET::::- Westmont
  
  BULLET::::- Willowbrook (also in the 323 area code)
  
  Section::::Splits and overlay controversy.
  
raw_presuppositions: Area codes were issued by location from west to east. Area codes were given out in sequential order.
raw_corrections: Location does not determine how area codes are issued to states. The simpler and easier to remember area codes were given to the largest cities.