Area code 423 serves eastern Tennessee, including cities such as Chattanooga, Johnson City, Kingsport, and Cleveland. It was created in 1995 from a split of area code 615 and was later overlaid in part by 865 to cover the Knoxville metro area. The 423 region encompasses both urban and rural areas, part of the Appalachian Mountains and the Tri-Cities area. With a strong presence in healthcare, education, and logistics, it plays a key role in the state’s economic landscape. 423 remains a standalone code in its area and is closely associated with the culture and geography of East Tennessee.