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 an area surrounding 412 in the southwestern corner of the state. Area code 878 was activated on August 17, 2001.
Area code 412 had served southwestern Pennsylvania for 41 years since 1947, before area code 724 was created for most of the old 412 territory outside of Pittsburgh in 1998. Bell Atlantic (now part of Verizon), the main telephone provider in the area, wanted to implement 724 as an overlay to spare residents and businesses the burden of changing their numbers. However, overlays were still a new concept at the time, and met with considerable resistance due to the need for ten-digit dialing. Thus, the relief plan was changed to a geographic area code split. Within two years, however, both 412 and 724 were in jeopardy of exhaustion. Overlays had gained more acceptance by then, so 878 was implemented as an overlay. It was activated on August 17, 2001. [1]
Although ten-digit dialing has been mandatory in southwestern Pennsylvania since 2001, no 878 numbers were assigned for more than a decade due to number-conservation procedures implemented in both Pittsburgh itself and the suburbs. On February 15, 2013, the Pennsylvania Public Utility Commission announced it would start to issue 878 numbers in the 724 territory sometime within the next year, as 724 was nearly exhausted. [2] The first 878 numbers were assigned in April 2013, nearly 12 years after the overlay was activated. [3]
On September 15, 2015, the first prefix (999) was assigned in the 412 territory. [4]
As of February 2020, Verizon is issuing 878 telephone numbers for 412's original territory.
The North American Numbering Plan 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 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.
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 1,000 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 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 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 717 and 223 are telephone area codes in the North American Numbering Plan (NANP) for South Central Pennsylvania and the Susquehanna Valley. The numbering plan area (NPA) includes the Harrisburg, Lancaster, and York metropolitan areas and a considerable portion of Pennsylvania Dutch Country, an area with nearly two million people.
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 408 and 669 are telephone area codes in the North American Numbering Plan (NANP) in the U.S. state of California. The numbering plan area comprises most of Santa Clara County and Northern Santa Cruz County, and includes Gilroy, Morgan Hill, Saratoga, Los Gatos, Monte Sereno, Milpitas, Sunnyvale, Santa Clara, Cupertino, Campbell, and San Jose.
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 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 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 code 412 is a telephone area code in the North American Numbering Plan (NANP) for the Commonwealth of Pennsylvania. The numbering plan area (NPA) comprises the city of Pittsburgh, most of surrounding Allegheny County, and small portions of Washington and Westmoreland counties. The area code was one of the original North American area codes created in 1947, when it was assigned to the entire southwestern corner of the state. On August 17, 2001, the numbering plan area was converted to an overlay complex with area code 878, which also forms an overlay with area code 724, in the surroundings of the 412 service area.
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 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.
| North: 814 | ||
| West: 304/681, 330/234, 440/436 | 412/878 and 724/878 | East: 814 |
| South: 304/681 | ||
| Ohio area codes: 216, 330/234, 419/567, 440/436, 513/283, 614/380, 740/220, 937/326 | ||
| West Virginia area codes: 304/681 | ||