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.
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 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 909 and 840 are telephone area codes in the North American Numbering Plan for the far-eastern part of Los Angeles County and southwestern San Bernardino County in the U.S. state of California. Area code 909 was created on November 14, 1992, in an area code split of 909, and 840 was added to the numbering plan area to form an overlay complex effective February 23, 2021.
Area codes 202 and 771 are telephone area codes in the North American Numbering Plan (NANP) for Washington, D.C.
Area codes 608 and 353 are telephone area codes in the North American Numbering Plan for much of southwestern Wisconsin, including the state capital city Madison. Area code 608 was assigned in 1955 to a numbering plan area created from areas with area code 414 and area code 715, and was the third area code created in Wisconsin. Rapid growth of the area, specifically in Dane County, brought the area code close to exhaustion of central office prefixes, with NANPA projections in 2022 projecting the need for relief by late 2023. In September 2022, the Wisconsin Public Service Commission and North American Numbering Plan Administrator (NANPA) announced an overlay complex for the numbering plan area with new area code 353, with an in-service date of September 15, 2023. New central office code orders were accepted starting on July 11, 2023, but activatlon is contingent on complete exhaustion of central office codes for 608.
Area codes 678, 470, and 943 are telephone area codes in the North American Numbering Plan (NANP) for the U.S. State of Georgia in the Atlanta metropolitan area. The area codes are assigned in an overlay plan to a combined numbering plan area (NPA) consisting of 404 and 770.
Area codes 610, 484, and 835 are telephone area codes in the North American Numbering Plan (NANP) for the eastern and southeastern regions of Pennsylvania. The numbering plan area (NPA) includes regions to the west of Philadelphia and the cities Allentown, Bethlehem, and Reading. It includes much of the Delaware Valley, including almost all of Delaware County, most of the Philadelphia Main Line, and all of the Lehigh Valley.
Area codes 570 and 272 are telephone area codes in the North American Numbering Plan (NANP) for the northeast quadrant of the U.S. state of Pennsylvania. The numbering plan area (NPA) includes the cities or towns of Scranton, Wilkes-Barre, Williamsport, Stroudsburg, East Stroudsburg, Pittston, Carbondale, Hazleton, Clarks Summit, Towanda, Bloomsburg, Sayre, Tunkhannock, Berwick, Milford, Montrose, Honesdale, Pocono Pines, Nanticoke, Tamaqua, Shavertown, Dallas, Mahanoy City, Sunbury, Jim Thorpe, and as far south as Pottsville and as far west as Lock Haven.
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 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 814 and 582 are telephone area codes in the North American Numbering Plan (NANP) for the northwestern and central portions of the Commonwealth of Pennsylvania. Cities served by the area code include Altoona, Bradford, DuBois, Erie, Meadville, Oil City, Titusville, Johnstown, St. Marys, and Warren as well as the boroughs of State College, Brockway, Clearfield, Huntingdon, Mount Union, Bedford, Clarion, Punxsutawney, Tyrone, Ebensburg, Coudersport, Ridgway and Brookville. Area code 814 is the original area code assigned to the numbering plan area in 1947. Area code 582 was activated in the service area as an additional code to form an overlay numbering plan with a starting date of October 3, 2020.
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 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 code 878 is an area code in the North American Numbering Plan for Southwestern Pennsylvania, centered in Pittsburgh. It forms an overlay complex with two distinct numbering plan areas, 412 in Pittsburgh and some suburban areas and 724 in surrounding 412 in the southwestern corner of the state. Area code 878 was activated on August 17, 2001.
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 code 724 is a telephone area code in the North American Numbering Plan for the Commonwealth of Pennsylvania in western and southwestern Pennsylvania, including a portion of the suburbs of Pittsburgh. It was created in an area code split of area code 412 on February 1, 1998, which made the 412 numbering plan area (NPA) an enclave for the city, with 724 surrounding 412. In 2001, area codes 412 and 724 were overlaid with area code 878, so that the entire southwestern corner of Pennsylvania is served by area code 878.
