Published: July 27, 2023
The first quarter of 2025 will bring a new area code to Eastern Tennessee locations currently served by the 423 Numbering Plan Area Code. NPA 423 covers two separate geographic areas with NPA 865 neighboring both. The new 729 overlay NPA is scheduled to enter service in March 2025 and will cover the same geographic areas currently using area code 423. There will also be a transition from 7 to 10 digits for local dialing within the new NPA overlay complex 423/729.