A new area code number is coming to the 423 counties located in East Tennessee.The new area code, 729, was approved on May 30 by the Tennessee Public Utilities Commission.According to the Public Utility Commission, counties with a 423-area code are expected to run out of new numbers in the third quarter of 2025. The new code is to make sure residents and businesses have access to a ‘sufficient supply’ of telephone numbers to serve the area.