Local access and transport area

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Map of LATAs in the US

Local access and transport area (LATA) is a term used in U.S. telecommunications regulation. It represents a geographical area of the United States under the terms of the Modification of Final Judgment (MFJ) entered by the United States District Court for the District of Columbia in Civil Action number 82-0192 or any other geographic area designated as a LATA in the National Exchange Carrier Association, Inc. Tariff FCC No. 4. that precipitated the breakup of the original AT&T into the "Baby Bells" or created since that time for wireline regulation.

Generally, a LATA represents an area within which a divested Regional Bell Operating Company (RBOC) is permitted to offer exchange telecommunications and exchange access services. Under the terms of the MFJ, the RBOCs are generally prohibited from providing services that originate in one LATA and terminate in another.

LATA boundaries tend to be drawn around markets, and not necessarily along existing state or area code borders. Some LATAs cross over state boundaries, such as those for the New York metropolitan area and Greenwich, Connecticut; Chicago, Illinois; Portland, Oregon; and areas between Maryland, Virginia, and West Virginia. Area codes and LATAs do not necessarily share boundaries; many LATAs exist in multiple area codes, and many area codes exist in multiple LATAs.

Originally, the LATAs were grouped into regions within which one particular RBOC was allowed to provide services. The LATAs in each of these regions are numbered beginning with the same digit. Generally, the LATAs were associated with carriers or other indications in the following manner:

Digit Area/Use RBOC
0xx unused
1xx New York & New England NYNEX (now Verizon and Consolidated Communications)
2xx Mid-Atlantic Bell Atlantic (now Verizon and Frontier)
3xx Great Lakes Ameritech (now AT&T Inc.)
4xx Southeast BellSouth (now AT&T Inc.)
5xx South-central Southwestern Bell (now AT&T Inc.)
6xx Pacific Northwest, Midwest, and Rocky Mountains US West (now CenturyLink)
7xx California and Nevada Pacific Bell (now AT&T Inc.)
8xx Non-contiguous and international areas
9xx Other/Expansion

In addition to this list, two local carriers were made independent: Cincinnati Bell in the Cincinnati area, and SNET (a former unit of AT&T, sold to Frontier) in Connecticut. These were assigned LATAs in the 9xx range.

Since the breakup of the original AT&T in 1984, however, some amount of deregulation, as well as a number of phone company mergers, have blurred the significance of these regions. A number of new LATAs have been formed within these regions since their inception, most beginning with the digit 9.

LATAs contribute to an often confusing aspect of long-distance telephone service. Due to the various and overlapping regulatory limitations and inter-business arrangements, phone companies typically provide differing types of “long distance” service, each with potentially different rates:

  • within same LATA, within same state
  • within same LATA, between different states
  • between different LATAs, within same state
  • between different LATAs, between different states

Given the complexity of the legal and financial issues involved in each distinction, many long-distance companies tend to not explain the details of these different rates, which can lead to billing questions from surprised customers.

Local carriers have various alternative terms for LATAs such as “Service Area” by Pacific Bell in California, or “Regional Calling Area” by Verizon in Maryland.

To facilitate the sharing of Telcordia telephone routing databases between countries, LATAs were later defined for the provinces of Canada, the other countries and territories of the North American Numbering Plan, and Mexico. Aside from U.S. territories, LATAs have no regulatory purpose in these areas. In 2000, the Canadian Radio-television and Telecommunications Commission eliminated all Canadian provincial LATAs in favor of a single LATA for Canada (888).

No LATAs exist with a second digit of 0 or 1, which distinguished them from traditional area codes.

List of LATAs[edit]

US state LATAs[edit]

The city or place name given with some LATAs is the name given to identify the LATA, not the limit of its boundary. Generally this is the most significant metropolitan area in the LATA. In some cases, a LATA is named after the largest phone exchange in the LATA that was historically served by an RBOC. For example, the largest city in the Pahrump LATA in Nevada is Las Vegas. Since Las Vegas was not historically served by an RBOC, the LATA is named after the smaller town of Pahrump, which was historically served by Nevada Bell (now AT&T Inc.). Also, listing under a state does not necessarily limit the LATA's territory to that state; there may be overlaps as well as enclaves. Areas that include notable portions of other states are explained, but not all LATA state overlaps may be detailed.

LATA boundaries are not always solidly defined. Inter-carrier agreements, change proposals to the Federal Communications Commission (FCC), and new wiring developments into rural areas can and do often alter the effective borders between LATAs. Many sources on LATA boundary information conflict with each other at detailed levels. Telcordia data may provide the most up-to-date details of LATA inclusions.



  • 832






  • 920

Washington, D.C.[edit]


Map of FL 5-digit LATAs



  • 834









  • 120



  • 126 Western Massachusetts
  • 128 Eastern Massachusetts





  • 520 St. Louis
    • Includes part of south-central Illinois southwest of Springfield.
  • 521 Westphalia (per locallingguide.com, includes Columbia MO)
  • 522 Springfield
  • 524 Kansas City
    • Includes eastern portion of Kansas as far out as U.S. 73 and U.S. 59 and south as far as U.S. 54
  • 521 Central Missouri: Columbia and surrounding areas


  • 648 Great Falls
  • 650 Billings
  • 963 Kalispell (historical)
    • note: LATA 963 appears on many LATA lists, and at least one map, but is no longer a separate LATA-equivalent area. It is now part of LATA 648.



New Hampshire[edit]

New Jersey[edit]

New Mexico[edit]

  • 664

New York[edit]

North Carolina[edit]

North Dakota[edit]





Rhode Island[edit]

  • 130 Rhode Island

South Carolina[edit]

South Dakota[edit]

  • 640







West Virginia[edit]

  • 254 Charleston
  • 256 Clarksburg
  • 240 Martinsburg
  • 932 (overlap with VA)


  • 350 Northeast Wisconsin
  • 352 Northwest Wisconsin
  • 354 Southwest Wisconsin
  • 356 Southeast Wisconsin


  • 654 Wyoming

U.S. territory LATAs[edit]

Non-U.S. LATAs (non-regulatory)[edit]


As LATAs exist for US regulatory purposes, where they serve as a demarcation between intra-LATA calls (handled by regional Bell operating companies) and inter-LATA calls (handled by interstate long-distance carriers such as AT&T), they have no legal significance in Canada.

As of 2000, all of Canada (except for non-geographic numbers) is identified as LATA 888.

The use of this LATA set to identify individual provinces is therefore deprecated:

Local interconnection region[edit]

Canada does define local interconnection regions (LIR's), which determine where points of interconnection (POI) must be provided by competing local exchange and mobile carriers to provide local number portability.[4] A Canadian LIR is geographically smaller than a US LATA, typically comparable in size to a small city's flat-rate local calling area or to an entire large regional municipality. In areas where a small-city Digital Multiplex System controls a group of remote switching centres, one for each surrounding village, the local interconnect region normally includes each exchange in the city plus all downstream remotes of those exchanges.[5] In a Toronto-sized city, the LIR will include only the city itself.

While the LIRs resemble local calling areas in geographic size, there are some key differences:

  • LIR's normally do not include incumbent local independent telephone company exchanges in locations not opened to competition, where the independent numbers are currently not portable.
  • LIR's do not cross provincial boundaries. Lloydminster has an LIR for each province, as does Ottawa-Hull.
  • LIR's closely follow network topology, which often does not match a local flat-rate calling area as local calling is defined by arbitrary regulatory constructs.

One example: The tiny unincorporated village of Beebe Plain, divided by the Quebec-Vermont border, is served by +1-819-876 Rock Island, Quebec, Canada (a remote station controlled from Magog) and +1-802-873 Derby Line, Vermont, USA (a remote station controlled from St. Johnsbury). Magog and St. Johnsbury are both a long-distance call from anywhere in Beebe Plain, even though Canadian subscribers can place local calls to Sherbrooke, US subscribers can locally call Newport and an international call within the village is local. An LIR assignment which follows network topology places the Canadian remote station in Magog's LIR, not Sherbrooke's LIR.[6]

See also[edit]


  1. ^ a b Half of LATA 636 occupies eastern North Dakota, the other half takes up the northwest quarter of Minnesota.
  2. ^ LATA 228 includes all of Delaware as well as the metro area of Philadelphia, Pennsylvania.
  3. ^ American Samoa entered the NANP in October 2004 and presumably was allocated a LATA by that time. Telcordia LERG data suggests that American Samoa uses LATA 884.
  4. ^ "Rogers Wireless Partnership Part VII application regarding the requirement for a central office code in each served exchange". 12 April 2007.
  5. ^ List of Canadian LIRs on localcallingguide.com
  6. ^ Rock Island QC on localcallingguide.com