Area codes 903 and 430 are telephone area codes in the North American Numbering Plan (NANP) for the northeastern part of the U.S. state of Texas, including Kilgore, Texarkana, Tyler, and Sherman.
The numbering plan area begins just north and east of the Dallas–Fort Worth metroplex, and extends to the Oklahoma, Arkansas, and Louisiana state borders.
From 1962 until October 18, 1980, area code 903 was an area code for parts of northwestern Mexico served by Telefónica Fronteriza, which homed on AT&T lines in the United States rather than Telefonos de Mexico (Telmex).
Telmex and the Mexican government forcibly acquired the TF exchanges, and in 1980, Telmex reorganized the area codes of the country, assigning 6 as the initial digit of 8-digit numbers in the northwest.
In February 1991, 706 and 905 were withdrawn pending assignment within the NANP service area.