Area code 318 is a telephone area code in the North American Numbering Plan (NANP) for the northern and central parts of the U.S. state of Louisiana. The area code was assigned in 1957 in an area code split of area code 504, to a numbering plan area that comprised nearly all of the state west of the Mississippi River, stretching from the Gulf of Mexico north to the border with Arkansas. In 1999, the southern half of the original 318, including Lafayette and Lake Charles, received area code 337.
During the initial trials of direct distance dialing (DDD) in 1951, area code 318 was temporarily used as a destination code for San Francisco. Oakland and San Francisco had separate toll switches, so that calls had to be routed accordingly depending on the final destination. As the telephone equipment used at the time handled only three-digit translation, the temporary use of a distinct area code was required to distinguish between the two Bay Area cities. Area code 318 was used temporarily to specify San Francisco and areas north of the Golden Gate Bridge, while calls with destinations in Oakland or the East Bay used area code 415. When the electromechanical card-translator became available by 1953, translations using six digits were possible; the 318 code no longer was required. The entire San Francisco Bay Area returned to using area code 415.
In 1957, Louisiana's original area code 504 was split to create a numbering plan area with area code 318 for all of the state west of the Mississippi River, stretching from the Gulf of Mexico north to the border with Arkansas.
In 1999, the southern half, including Lafayette and Lake Charles, was split off with area code 337.
Further relief will be required in the near future, as 318 is expected to exhaust by early 2026. [1] An overlay complex (the first in Louisiana) will be created with area code 457 and will take effect beginning September 25, 2025. [2] A transition to ten-digit dialing will be undertaken ahead of the overlay.
Direct distance dialing (DDD) is a telecommunication service feature in North America by which a caller may, without operator assistance, call any other user outside the local calling area. Direct dialing by subscribers typically requires extra digits to be dialed as prefixes to the directory telephone number of the destination. International Direct Distance Dialing (IDDD) extends the system beyond the geographic boundaries of the North American Numbering Plan (NANP).
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 415 and 628 are telephone area codes in the North American Numbering Plan (NANP) for the city of San Francisco and its northern suburbs in Marin County, and the northeast corner of San Mateo County in the U.S. state of California. Area code 415 was one of the eighty-six original North American area codes established in 1947, but modified in geographic configuration later. Area code 628 was assigned in 2015 to form an overlay in that numbering plan area in mitigation of central office prefix exhaustion.
Area codes 954 and 754 are the telephone area codes in the North American Numbering Plan (NANP) for Broward County, Florida. Notable cities in the numbering plan area are Fort Lauderdale, Plantation, Hollywood, Parkland, Sunrise, Pompano Beach, Coral Springs, Deerfield Beach, Davie, Weston, Dania Beach, Oakland Park and Pembroke Pines.
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.
Seven-digit dialing is a telephone dialing procedure customary in some territories of the North American Numbering Plan (NANP) for dialing telephone numbers in the same numbering plan area (NPA). NANP telephone numbers consist of ten digits, of which the leading three are the area code. In seven-digit dialing it is not necessary to dial the area code. The procedure is also sometimes known as local format or network format.
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 541 and 458 are telephone area codes in the North American Numbering Plan (NANP) for most of the U.S. state of Oregon, excluding only the northwestern corner of the state. The service area includes the cities of Eugene, Springfield, Corvallis, Albany, Medford, Bend, Ashland, Klamath Falls, The Dalles, Burns, Lakeview, and Pendleton, as well as the coastal region from Lincoln County to the California border. Area code 541 was created in an area code split from area code 503 on November 5, 1995. Area code 458 was added to the same service area on February 10, 2010 to form an overlay.
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 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 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 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 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 510 and 341 are telephone area codes in the North American Numbering Plan (NANP) serving much of the East Bay in the U.S. state of California. They cover parts of Contra Costa County and western Alameda County, including the city of Oakland, but excluding Dublin, Livermore, Pleasanton, and Sunol.
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 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 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 870 and 327 are telephone area codes in the North American Numbering Plan (NANP) for southern, eastern, and most of northern Arkansas. 870 was created on April 14, 1997 in a split from area code 501, Arkansas's original area code of 1947 and 327 was added as part of an overlay complex in 2024.
| North: 870/327 | ||
| West: 409, 903/430, 936 | 318 | East: 601/769, 662 |
| South: 225, 337 | ||
| Arkansas area codes: 479, 501, 870/327 | ||
| Mississippi area codes: 228, 601/769, 662 | ||
| Texas area codes: 210/726, 214/469/972/945, 254, 325, 361, 409, 432, 512/737, 713/281/832/346, 806, 817/682, 830, 903/430, 915, 936, 940, 956, 979 | ||