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.
Area codes 314 and 557 are telephone area codes in the North American Numbering Plan (NANP) in the U.S. state of Missouri, serving the city of St. Louis and most of its inner-ring suburbs in neighboring St. Louis County. The numbering plan area is bordered to the west by area code 636, which serves St. Louis' outer suburbs to the west, south, and north. Across the Mississippi River to the east, 314 is adjacent to area code 618, which serves southern Illinois and most of Metro East. Area code 557 was added to the 314 numbering plan area on August 12, 2022, to form an overlay numbering plan.
Area codes 850 and 448 are telephone area codes in the North American Numbering Plan for the Florida panhandle, including Pensacola, Tallahassee and Panama City. Area code 850 was created in 1997 in a split from 904, and area code 448 was assigned as a second code to the same area in an overlay plan in 2019, and mandatory ten-digit local calling began in May 2021.
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 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 305, 786, and 645 are telephone area codes in the North American Numbering Plan (NANP) for Miami, Florida, Miami-Dade County, and the part of Monroe County in the Florida Keys in the United States. The mainland portion of Monroe County is served by area code 239.
Area codes 813 and 656 are area codes in the North American Numbering Plan for the U.S. state of Florida in the city of Tampa, Florida, and its surrounding areas, such as Zephyrhills and Oldsmar. In 2022, due to exhaustion of central office prefixes, area code 656 was added to the service area forming an overlay complex.
Area codes 812 and 930 are telephone area codes in the North American Numbering Plan (NANP) for the southern third of the state of Indiana.
Area codes 301, 240, and 227 are telephone area codes in the North American Numbering Plan (NANP) for the western part of the U.S. state of Maryland. The numbering plan area (NPA) comprises Maryland's portion of the Greater Washington, D.C. metro area, portions of southern Maryland, along with rural western Maryland. This includes the communities of Cumberland, Frederick, Hagerstown, Gaithersburg, Potomac, Germantown, Bethesda, Rockville, Landover, Silver Spring, and Waldorf.
Area codes 904 and 324 are telephone area codes in the North American Numbering Plan for most of the First Coast (northeast) region of the U.S. state of Florida. The numbering plan area comprises most of the metropolitan area of Jacksonville. It includes all of Duval County, St. Johns County, Nassau County, and Baker County, and almost all of Clay County. Area code 904 was created in an area code split of area code 305 in 1965. In 2024, the numbering plan received a second area code, 324, through the creation of an overlay complex to mitigate central office code exhaustion and provide additional telephone numbers in the area.
Area codes 609 and 640 are telephone overlay area codes in the North American Numbering Plan (NANP) for the central and southern parts of the U.S. state of New Jersey. The numbering plan area includes the cities of Trenton, Princeton, Ewing, Hamilton, and southeastern parts of the state and the Jersey Shore, including Atlantic City and Long Beach Island. In terms of geographic coverage, it is the largest numbering plan area in New Jersey. Area code 609 was created in a split of area code 201 in c. 1956. Area code 640 is an additional area code for the area, created on September 17, 2018.
Area codes 513 and 283 are telephone area codes in the North American Numbering Plan (NANP) for the southwest of the U.S. state of Ohio, including Cincinnati and surrounding cities, such as Forest Park, Hamilton, Lebanon, West Chester, Mason, Maineville, Middletown, Milford, Norwood, Oxford, Harrison, Cleves, Miamitown and Trenton.
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 618 and 730 are telephone area codes in the North American Numbering Plan (NANP) for southern Illinois. The numbering plan area (NPA) comprises one hundred and twenty-six municipalities, such as Carbondale, Cairo, Belleville, East St. Louis, Edwardsville, Marion, O'Fallon, Alton, Mt. Vernon, Centralia, Herrin, Salem, Metropolis, Fairview Heights, Collinsville, and Granite City. Area code 618 was one of the original North American area codes created in 1947, and 730 was added to the plan area to form an overlay complex to satisfy the need for more telephone numbers in the region. The current population of the 618/730 area code is 1,288,816 people. It encompasses approximately 15,458 square mile ; and has a population density of 83.38 people per square mile.
Area codes 937 and 326 are telephone area codes in the North American Numbering Plan (NANP) assigned to a numbering plan area (NPA) that encompasses much of the southwestern part of the U.S. state of Ohio, including Dayton and Springfield. Area code 937 was established in September 1996, in a split of area code 513. Area code 326 was added to the numbering plan area to form an overlay complex in March 2020.
Area codes 270 and 364 are telephone overlay area codes in the North American Numbering Plan (NANP) for the Commonwealth of Kentucky's western and south central counties. Area code 270 was assigned in a split of numbering plan area 502 in 1999. Area code 364 was added to the same numbering plan area on March 3, 2014, after having been first considered for 270-relief planning in 2007. Major cities in the numbering plan area include Hopkinsville, Paducah, Henderson, Murray, Bowling Green, Owensboro, Elizabethtown, and Madisonville. It also includes Kentucky's share of Fort Campbell.
