Area code 423 serves eastern Tennessee, including cities like Chattanooga, Johnson City, and Kingsport. Established in 1995 from a split with area code 615, 423 encompasses both the Tri-Cities region in the northeast and Chattanooga in the southeast, separated by the 865 area. The area blends Appalachian heritage with growing economic sectors like healthcare, education, and logistics. Chattanooga has become a hub for startups and outdoor recreation, while the Tri-Cities maintain strong ties to history and industry. Ten-digit dialing is required in many areas. Area code 423 represents a diverse and evolving corner of Tennessee, balancing old and new.