The area code 423 is located in Chattanooga, Tennessee.
Area code 423 serves the eastern part of Tennessee, anchoring the region around Chattanooga and the Tri-Cities. It’s unique because it covers two separate areas—one in the southeast around Chattanooga and one in the northeast around Johnson City, Kingsport, and Bristol—split by the Knoxville region. This area code sits in the Eastern Time Zone and stretches across the Appalachian foothills, the Tennessee River valley, and parts of the Cherokee National Forest. It connects major travel corridors like I‑24, I‑75, I‑26, and I‑81, making it a key hub for calls across East Tennessee.
Coverage includes major cities and well-known landmarks:
Established: 1995; Split creating 865 (Knoxville): 1999 — Source: North American Numbering Plan Administration (NANPA)
Created in 1995 from the old 615 area, 423 later gave up the Knoxville area in 1999 when 865 was introduced (chosen because 8‑6‑5 spells “VOL,” a nod to the Tennessee Volunteers). Today, when you see a 423 phone number, it typically traces back to either the Chattanooga metro area or the Tri-Cities region. The code’s two-section layout is a helpful clue: it does not cover Knoxville, the Smokies tourist towns like Gatlinburg or Pigeon Forge, or Middle Tennessee. In short, 423 is the go-to area code for much of East Tennessee, from riverfront Chattanooga to NASCAR-famous Bristol.