Area codes 423 and 729
telephone area code in east Tennessee, United States
Area codes 423 and 729 are telephone area codes in the North American Numbering Plan (NANP) for the U.S. state of Tennessee. The numbering plan area comprises two geographically disjoined areas of East Tennessee, separated by numbering plan area 865, as well as portions of Van Buren and Sequatchie counties in Middle Tennessee.
Principal cities in the northern part of the numbering plan area are Morristown, Greeneville, and the Tri-Cities (Kingsport, Johnson City, Bristol). The principal cities in the south are Chattanooga and Cleveland.
History
When the American Telephone and Telegraph Company created the first nationwide telephone numbering plan for Operator Toll Dialing, the predessessor of the North American Numbering Plan, in 1947, Tennessee was a single numbering plan area (NPA) with area code 901. In 1954, 901 was reduced to West Tennessee, while the rest of the state received area code 615.
In 1995, the eastern portion of 615, including Knoxville, Chattanooga, and the Tri-Cities, was split off with area code 423. This was the first new area code in the state in 41 years.
The boundary between 423 and 615 roughly followed the line between the Eastern and Central time zones; generally, Tennessee's share of the Eastern Time Zone was in 423. As a result, the state's three area codes were roughly coextensive with the traditional Grand Divisions of Tennessee.
The public source identifies “Area codes 423 and 729” as telephone area code in east Tennessee, United States. This brief keeps that definition visible, then builds a research path around Area, codes and telephone.
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Named sources, stable identifiers and responsible institutions provide the strongest route from overview to verifiable evidence. The source revision retrieved here is dated Mar 7, 2026. The linked authority identifier is Q4788577. None of the 0 selected statements returned an explicit reference. The first chronological checks are 1947, 1954 and 1995.
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This entry incorporates text from “Area codes 423 and 729” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.