Area codes 416, 647, and 437 are telephone area codes in the North American Numbering Plan (NANP) for the city of Toronto, Ontario, Canada. Area code 416 is one of the original North American area codes created by the American Telephone and Telegraph Company (AT&T) in 1947. Area codes 647 and 437 are additional area codes for the same numbering plan area (NPA), forming an overlay numbering plan.
In telecommunications, an area code overlay complex is a telephone numbering plan that assigns multiple area codes to a geographic numbering plan area (NPA). Area code overlays are implemented in territories of the North American Numbering Plan (NANP) to mitigate exhaustion of central office codes in growth areas. The method has been in use since 1992, and has been the preferred and exclusive method of relief since 2007.
Ten-digit dialing is a telephone dialing procedure in the countries and territories that are members of the North American Numbering Plan (NANP). It is the practice of including the area code of a telephone number when dialing to initiate a telephone call. When necessary, the ten-digit number may be prefixed with the trunk code 1, which is referred to as 1+10-digit dialing or national format.
Telephone number pooling, thousands-block number pooling, or just number pooling, is a method of allocating telephony numbering space of the North American Numbering Plan in the United States. The method allocates telephone numbers in blocks of one thousand consecutive numbers of a given central office code to telephony service providers. In the United States it replaced the practice of allocating all 10,000 numbers of a central office prefix at a time. Under number pooling, the entire prefix is assigned to a rate center, to be shared among all providers delivering services in that rate center. Number pooling reduced the quantity of unused telephone numbers in markets which have been fragmented between multiple service providers, avoided central office prefix exhaustion in high growth areas, and extended the lifetime of the North American telephone numbering plan without structure changes of telephone numbers. Telephone number pooling was first tested for area code 847 in Illinois in June 1998, and became national policy in a series of Federal Communications Commission (FCC) orders from 2000 to 2003.
Area code 312 is a telephone area code in the North American Numbering Plan for the city of Chicago, including downtown, the Chicago Loop, and its immediate environs. The numbering plan area is completely surrounded by area code 773, which serves the rest of Chicago. Both area codes form an overlay complex with area code 872. 312 is an enclave area code, and is roughly bounded by North Avenue on the north, Western Avenue on the west, and 35th Street on the south, with Lake Michigan to the east. In terms of geographic area covered, 312 is one of the smallest area codes in the nation, encompassing only a few square miles.
Area codes 614 and 380 are telephone area codes in the North American Numbering Plan (NANP) for all or part of four counties in central Ohio, surrounding and including the state capital of Columbus. Area code 614 is one of the original area codes assigned for Ohio in 1947, while area code 380 is an overlay code covering the same territory.
Area codes 630 and 331 are telephone area codes in the North American Numbering Plan (NANP) for portions of Chicago's near and far western suburbs, including the majority of DuPage County, Illinois. To the northwest, the numbering plan area (NPA) also includes a small portion of Cook County, including parts of Schaumburg, Streamwood and Hanover Park. To the west, Kane County is divided between area codes 847 and 224 in the north, including Elgin, and area codes 630 and 331 in the south, including Aurora. To the south, the northern part of Will County and a small part of southern Cook County, including the village of Burr Ridge and parts of the village of Lemont, are also included in the 630 and 331 area codes. To the southwest, the city of Yorkville, in exurban Kendall County, is included, as well.
Area code 414 is a telephone area code of the North American Numbering Plan for the area around and including the city of Milwaukee in the state of Wisconsin.
Area codes 708 and 464 are telephone area codes in the North American Numbering Plan (NANP) for the southern and western suburbs of Chicago in the U.S. state of Illinois. The numbering plan area comprises most of western and southern Cook County, and eastern and southern Will County.
Area codes 514, 438, and 263 are telephone area codes of the North American Numbering Plan (NANP) for Montreal and most of its on-island suburbs, specifically the Island of Montreal and Île Perrot in the Canadian province of Quebec.
Area codes 202 and 771 are telephone area codes in the North American Numbering Plan (NANP) for Washington, D.C.
Area codes 615 and 629 are area codes in Tennessee serving Nashville and the 12 surrounding counties. 615 is the main area code, while 629 is an overlay covering the same area that began service in 2014. Murfreesboro, Franklin, Brentwood, Gallatin, Hendersonville, and Lebanon are other major cities in the 615/629 service territory.
Area codes 602, 480, and 623 are telephone area codes in the North American Numbering Plan (NANP) for most of the Phoenix metropolitan area in the U.S. state of Arizona.
Area codes 304 and 681 are telephone area codes in the North American Numbering Plan (NANP) for the entirety of the U.S. state of West Virginia. The numbering plan area was established in October 1947 with area code 304, as one of the eighty-six original North American area codes. Area code 681 was added to the same area in an overlay plan that took effect on March 28, 2009.
Area codes 215, 267, and 445 are telephone area codes in the North American Numbering Plan (NANP) for Philadelphia and adjacent portions of Bucks and Montgomery counties in the U.S. state of Pennsylvania. Area code 215 was one of the original North American area codes established in 1947, while 267 and 445 are overlay codes for the same numbering plan area (NPA).
Area codes 303, 720 and 983 are telephone area codes in the North American Numbering Plan for the north-central portion of the U.S. state of Colorado. The numbering plan area comprises Denver and Boulder, as well as their surrounding suburbs, including Lakewood, Littleton, Longmont, Broomfield, Aurora, and Castle Rock. Area code 303 is the original area code, while area codes 720 and 983 were added to form an overlay complex for the area, meaning that the same geographic service area is served by all area codes and that ten-digit dialing is required for all calls made within the service area.
Area code 816 is a telephone area code in the North American Numbering Plan (NANP) for Kansas City, St. Joseph, and all or part of 15 surrounding counties in northwestern Missouri. The numbering plan area originally comprised most of the northern and western two-thirds of the state, bordering with Arkansas, Illinois, Iowa, Kansas, Nebraska, and Oklahoma, but has been reduced to a ribbon bordering Kansas. 816 is one of the original 86 area codes created in 1947.
Area codes 703 and 571 are telephone area codes in the North American Numbering Plan (NANP) for Northern Virginia, including the independent cities of Alexandria, Fairfax, Falls Church, Manassas, and Manassas Park, as well as all of Arlington and Fairfax counties and parts of Fauquier, Loudoun, and Prince William counties. Area code 703 was created as one of the eighty-six original North American area codes in October 1947, and originally served the entire Commonwealth of Virginia. Area code 571 was created on March 1, 2000, to form an overlay plan with 703. The headquarters for The Chesapeake and Potomac Telephone Company of Virginia was at 703 East Grace Street, Richmond, Virginia.
Area code 773 serves Chicago, Illinois, outside the Loop and the innermost neighborhoods.
