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.