Area codes 519, 226, 548, and 382 are overlay telephone area codes in the North American Numbering Plan (NANP) for most of southwestern Ontario.
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 508 and 774 are telephone area codes in the North American Numbering Plan (NANP) for the U.S. state of Massachusetts. The numbering plan area comprises south-central and most of southeastern Massachusetts. It includes Worcester, Outer south and southwest Greater Boston, as well as Fall River, New Bedford, Cape Cod, Martha's Vineyard, and Nantucket.
Area codes 805 and 820 are telephone area codes in the North American Numbering Plan (NANP) for the U.S. state of California. The numbering plan area (NPA) includes most or all of the counties of San Luis Obispo, Santa Barbara, Ventura, and the southernmost portions of Monterey County. 805 was split from area code 213 in 1957, and area code 820 was added to the NPA in 2018, creating an area code overlay.
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 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 804 and 686 are telephone area codes in the North American Numbering Plan (NANP) for the east-central portion of Virginia. The numbering plan area is anchored by Virginia's capital, Richmond, and includes most of its metropolitan area. Other communities included are Chesterfield, Henrico, Hopewell, Mechanicsville, Powhatan, Midlothian, Petersburg, and Colonial Heights. This also includes the Northern Neck and the Middle Peninsula. The two southernmost counties on the Middle Peninsula, Gloucester and Mathews, are part of the Hampton Roads metropolitan area, but use 804 and 686 instead of the area codes 757 and 948 used by the rest of Hampton Roads.
Area codes 202 and 771 are telephone area codes in the North American Numbering Plan (NANP) for Washington, D.C.
Area code 413 is a telephone area code in the North American Numbering Plan (NANP) for the western third of Massachusetts. It is the largest numbering plan area in the Commonwealth, and extends from the New York state line eastward into Worcester County, while excluding the Franklin County towns of Orange, New Salem, Warwick, and Wendell, which use the overlay of area codes 978 and 351. The most-populous city of area code 413 is Springfield. 413 also includes Great Barrington, Greenfield, North Adams, Northampton and Pittsfield. The 413 numbering plan area constitutes local access and transport area (LATA) 126.
Area code 250 is a telephone area code in the North American Numbering Plan (NANP) for the Canadian province of British Columbia outside the Lower Mainland, including Vancouver Island–home to the provincial capital, Victoria–and the province's Interior region. In addition, the numbering plan area extends into the United States community of Hyder, Alaska, located along the Canada–United States border near the town of Stewart. The incumbent local exchange carriers that service the area code are Telus, Northwestel, and CityWest in the city of Prince Rupert.
Area codes 778, 236, and 672 are telephone area codes in the North American Numbering Plan (NANP) for the Canadian province of British Columbia. They form an overlay complex with area code 604, which serves only a small southwestern section, the Lower Mainland, of the province, and area code 250, which serves the rest of the province.
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 code 780 is a telephone area code in the North American Numbering Plan (NANP) for the Canadian province of Alberta. The numbering plan area comprises the northern two thirds of the province, including the Edmonton area. The area code was established in 1999 in a split of area code 403, which had served the entire province since the establishment of the original North American area codes in 1947. The numbering plan area is also served by area codes 587, 825, and 368, which form a complex overlay for all of Alberta.
Area code 604 is a telephone area code in the North American Numbering Plan for southwestern British Columbia, Canada. The numbering plan area comprises the Metro Vancouver, Sunshine Coast, Howe Sound / Sea to Sky Corridor, Fraser Valley and the lower Fraser Canyon regions. The major city is Vancouver. The area code is one of the nine original North American area codes assigned to Canada in 1947.
Area codes 617 and 857 are telephone area codes in the North American Numbering Plan (NANP) for the U.S. state of Massachusetts, serving the city of Boston and several surrounding communities such as Brookline, Cambridge, Newton and Quincy. Area code 617 is one of the original North American area codes created in October 1947, when it served the eastern two-thirds of Massachusetts, from roughly the western end of Worcester County to Cape Cod and the South Coast.
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 978 and 351 are telephone area codes in the North American Numbering Plan for north central and most of northeastern Massachusetts.
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 587, 825, and 368 are telephone area codes in the North American Numbering Plan (NANP) for the entire Canadian province of Alberta. They form an overlay with area code 403 of southern Alberta, and northern Alberta's 780. The complex overlay involving a total of five area codes in Alberta mandated ten-digit dialing throughout the province.
