The North American Numbering Plan (NANP) is a telephone numbering plan for twenty-five regions in twenty countries, primarily in North America and the Caribbean. This group is historically known as World Zone 1 and has the telephone country code 1. Some North American countries, most notably Mexico, do not participate with the NANP.
In telecommunications, an area code overlay complex is a telephone numbering plan that assigns multiple area codes to the same 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 exclusive method of area code 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.
Area codes 561 and 728 are telephone area codes in the North American Numbering Plan (NANP) for Palm Beach County in the U.S. state of Florida. 561 was created on May 13, 1996, in a split of area code 407. The numbering plan area (NPA) comprises nearly every major city in the county, the largest of which being West Palm Beach, Boca Raton, Wellington, Boynton Beach, Jupiter, Delray Beach, and Belle Glade. On March 10, 2023, area code 728 was added to the same numbering plan area to form an all-services distributed overlay.
Area codes 920 and 274 are telephone area codes in the North American Numbering Plan (NANP) for a large area of eastern Wisconsin. Area code 920 was created on July 26, 1997, in a split of area code 414, one of the original North American area codes of 1947. 274 was added to the same numbering plan area (NPA) on May 5, 2023 to create an area code overlay.
Area codes 212, 646, and 332 are area codes in the North American Numbering Plan (NANP) for most of the borough of Manhattan in New York City. By area, it is one of the smallest numbering plan areas (NPAs). The three area codes form an overlay numbering plan, and are also overlaid by area code 917 of a numbering plan area that comprises the entirety of New York City. Area code 212 is the original code assigned for all of the city in 1947. After a restriction of 212 to just Manhattan in 1985, area code 646 was assigned to Manhattan in 1999. In 2015, area code 332 was also added to the Manhattan overlay.
Area code 564 is a telephone overlay area code in the North American Numbering Plan (NANP) for Western Washington state, including metropolitan Seattle. The area code was first proposed in 1999 to relieve telephone number shortages in area code 360, but implementation was delayed until 2017, when it was installed for an overlay complex that comprises only the numbering plan area 360. Neighboring area codes 206, 253, and 425 were slated for expansion of the overlay upon exhaustion of central office codes in each NPA. In 2023, area code 206 was approved for expansion with a guide line for preparation of inclusion of at least nine months. Ten-digit dialing has been mandatory in all of western Washington since July 29, 2017.
Area codes 516 and 363 are telephone overlay area codes in the North American Numbering Plan (NANP) for the U.S. state of New York. The numbering plan area (NPA) comprises Nassau County on Long Island. Area code 516 was created in 1951 and 363 was added to the numbering plan area in 2023.
Area codes 718, 347, and 929 are telephone area codes in the North American Numbering Plan (NANP) for the New York City boroughs of the Bronx, Brooklyn, Queens, and Staten Island, as well as the Marble Hill section of Manhattan. They are part of a larger overlay plan with area code 917, which comprises all of New York City.
Area code 404 is a telephone area code in the North American Numbering Plan (NANP) for Atlanta, Georgia and its closest suburbs. This comprises roughly the area encircled by Interstate 285. It is an enclave area code, surrounded by area code 770, which serves most of Atlanta's suburbs. Both 404 and 770 are overlaid by area codes 678, 470, and 943.
Area codes 706 and 762 are telephone area codes in the North American Numbering Plan (NANP) for the northern and west central parts of Georgia, but excluding metropolitan Atlanta.
Area codes 402 and 531 are telephone area codes in the North American Numbering Plan (NANP) for the eastern part of the U.S. state of Nebraska. Area code 402 was one of the original North American area codes created in 1947, when it was assigned to the entire state. By splitting the numbering plan area (NPA) in 1954, it was reduced to roughly just the eastern half, including the state capital city Lincoln and Omaha, the largest city in the state. In 2011, the North American Numbering Plan Administrator (NANPA) authorized an overlay complex for which area code 531 was added to the same service area.
Area codes 203 and 475 are telephone area codes in the North American Numbering Plan (NANP) for the southwestern part of the U.S. state of Connecticut. The numbering plan area (NPA) is mostly coextensive with the Connecticut portion of the New York metropolitan area, and comprises most of Fairfield County, all of New Haven County, and a small portion of Litchfield County.
Area codes 876 and 658 are telephone area codes in the North American Numbering Plan (NANP) for Jamaica.
Area codes 801 and 385 are telephone area codes in the North American Numbering Plan (NANP) serving Salt Lake City and the four surrounding counties of the Wasatch Front in north-central Utah. The numbering plan area comprises Davis, Morgan, Salt Lake, Utah, and Weber counties. Other major towns and cities within the area are Alta, American Fork, Bountiful, Layton, Lehi, Murray, Ogden, Orem, Provo, Sandy, South Jordan, Spanish Fork, Taylorsville, West Jordan, and West Valley City. This numbering plan area is located in the Mountain Time Zone. Area code 801 is one of the original North American area codes created in 1947. Area code 385 was assigned to the same numbering plan area in 2008, creating an overlay complex.
Area code 403 is a telephone area code in the North American Numbering Plan (NANP) for the Canadian province of Alberta. The numbering plan area encompasses the southern third of the province, which includes the Calgary area. This numbering plan area is also served by area codes 587, 825, and 368, which form a complex overlay for all of Alberta.
Area codes 704 and 980 are telephone area codes in the North American Numbering Plan (NANP) for Charlotte and all or part of 12 surrounding counties in south-central North Carolina. Other major cities in the service area are Gastonia, Kannapolis, Concord, Mooresville, Salisbury, Statesville, and Shelby. The South Carolina side of the Charlotte metropolitan area is part of area codes 803 and 839. Area code 704 is one of the original area codes assigned to numbering plan areas (NPAs) by AT&T in October 1947. Area code 980 was added in an overlay numbering plan in 2000.
Area codes 573 and 235 are telephone area codes in the North American Numbering Plan (NANP) for most of the eastern half of the U.S. state of Missouri outside the immediate St. Louis area, including the state capital of Jefferson City, as well as Columbia, Cape Girardeau, Hannibal, Rolla, and Sikeston. The largest cities are Columbia, home to the University of Missouri, and Jefferson City, the state capital.The numbering plan area (NPA) extends across half of the width of the state, with the northeastern tip near the northeastern corner of the state, the Lake of the Ozarks at the western tip and Doniphan as the southwestern tip. They also serves all of southeastern Missouri and areas adjacent to the Mississippi River. 573 was created on January 7, 1996, in a split of area code 314, which was limited to the St. Louis metropolitan area in Missouri, and 235 was added on March 24, 2024 as part of an overlay complex.
Area codes 816 and 975 are telephone area codes in the North American Numbering Plan (NANP) for most of the Missouri side of the Kansas City metropolitan area, the St. Joseph area, 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. The numbering plan area was converted to an overlay complex with area code 975 in 2023.
Area codes 503 and 971 are telephone area codes in the North American Numbering Plan (NANP) for the northwestern region of the U.S. state of Oregon. The numbering plan area (NPA) comprises the cities of Portland, Salem, and Astoria. Area code 503 was one of the original North American area codes of 1947, assigned to the entire state until 1995, when its extent was reduced to the northwestern corner. Area code 971 was assigned to the service area in stages, completed in 2008, to form an overlay in the area with ten-digit dialing.
