The 423 area code serves the eastern edge of Tennessee, including Chattanooga in the south and the Tri-Cities of Johnson City, Kingsport, and Bristol in the northeast. Created in 1995 when it split from 615, 423 traces the Appalachian corner of the state along the Georgia, North Carolina, and Virginia borders.
Quick Summary of the 423 Area Code
| Area Code | 423 |
| State | Tennessee (TN) |
| Region | Chattanooga, Tri-Cities & East Tennessee |
| Major Cities | Chattanooga, Johnson City, Kingsport, Bristol, Cleveland, Morristown |
| Time Zone | Eastern Time (ET) – EST / EDT |
| Dialing Format | 7 or 10-digit dialing |
Geographic Coverage
The 423 area code covers a long crescent of eastern Tennessee, from Chattanooga and Cleveland in the southwest, along the Appalachian foothills, up to the Tri-Cities region of Johnson City, Kingsport, and Bristol in the far northeast, plus Morristown to the west. It borders Georgia, North Carolina, and Virginia and wraps around the 865 (Knoxville) area code.
Time Zone
The 423 area code observes Eastern Time (ET). Clocks follow Eastern Standard Time (UTC−5) in winter and shift to Eastern Daylight Time (UTC−4) from mid-March through early November. Because Tennessee straddles two time zones, note that eastern Tennessee runs one hour ahead of the Nashville and Memphis regions. From the West Coast, this area is three hours ahead of Pacific Time, so a 9:00 AM call in California reaches a 423 number at 12:00 PM local time.
Tip: Business hours across the 423 region generally run 9:00 AM to 5:00 PM local time, Monday through Friday.
How to Dial a 423 Number
Area code 423 is not part of an overlay, so it has traditionally allowed 7-digit local dialing. However, 10-digit dialing is now the recommended nationwide standard, and dialing the full 10-digit number (423 + the line number) always works reliably. For international callers, dial your country’s exit code, then +1 (the North American country code), then 423, followed by the seven-digit local number.
Scam Alerts for the 423 Area Code
Like every U.S. area code, 423 has been used by scammers who spoof local numbers to appear trustworthy. Residents in Chattanooga, Johnson City, Kingsport, Bristol, Cleveland, Morristown should stay alert to the following common tactics:
| Scam Type | What to Watch For |
|---|---|
| IRS / Tax Scams | Callers impersonating the IRS and threatening arrest over supposed unpaid taxes. |
| Utility Shut-off | Fake EPB or utility callers demanding instant payment to keep your power on. |
| Tech Support Fraud | Pop-ups or calls claiming your computer is infected and asking for remote access. |
| Medicare / Health Scam | Robocalls seeking Medicare numbers under the guise of free braces or test kits. |
If you receive a suspicious call from a 423 number, take these steps to protect yourself:
- Do not share personal information such as Social Security numbers, bank details, or passwords over the phone.
- Hang up and verify by calling the organization back using an official number from its website.
- Report the call to the FTC at reportfraud.ftc.gov and to the Tennessee Attorney General’s Office.
- Block the number and consider registering with the National Do Not Call Registry.
Red Flag: Legitimate agencies such as the IRS, Social Security Administration, or your local utility company will never demand immediate payment by gift card, wire transfer, or cryptocurrency. Any 423 caller making such a demand is a scammer.
History and Economy of the 423 Region
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Area code 423 was created in 1995, split from 615, to serve eastern Tennessee; four years later, in 1999, the Knoxville metro was carved out into the new 865 area code, leaving 423 to cover Chattanooga and the Tri-Cities. The regional economy is anchored by advanced manufacturing and healthcare. Chattanooga, nicknamed the “Gig City” for its pioneering municipal fiber network, hosts a major Volkswagen assembly plant and a growing technology sector along its revitalized riverfront. In the northeast, Kingsport is home to Eastman Chemical Company, one of the largest chemical manufacturers in the country, while Ballad Health anchors the Tri-Cities medical sector.
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Looking Up a 423 Number
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To find out who is calling from a 423 number, run a reverse phone lookup or search the full 10-digit number online. Chattanooga and Tri-Cities businesses, hospitals, and government offices publish their 423 numbers widely, so a legitimate caller is often easy to confirm with a quick search.
Nearby & Related Area Codes
Tennessee is served by several area codes. If you are researching 423, these neighboring and overlay codes are worth knowing:
You can also browse our full directory of Tennessee area codes for more regional guides.
↑ See the complete list of All US Area Codes by State – every area code across all 50 states in one directory.
Explore Neighboring States
Researching area codes just across the state line? Start with these codes in the states that border Tennessee:
- Kentucky – area code 502
- Virginia – area code 804
- North Carolina – area code 704
- Georgia – area code 404
- Alabama – area code 205
- Mississippi – area code 601
- Arkansas – area code 501
- Missouri – area code 314
Frequently Asked Questions
Where is the 423 area code located?
The 423 area code covers eastern Tennessee, including Chattanooga and Cleveland in the south and the Tri-Cities of Johnson City, Kingsport, and Bristol in the northeast.
Does 423 have an overlay?
No. The 423 area code covers its East Tennessee region on its own and currently has no overlay code.
Do I need to dial 10 digits for 423?
Because 423 has no overlay, 7-digit local dialing has historically worked, but dialing the full 10 digits is now the recommended standard and always works.
What time zone is the 423 area code in?
The 423 area code observes Eastern Time (EST/EDT), like the Knoxville region to its west.
Related 423 Guides
- Is a 423 call safe? Read Is area code 423 a scam? Spam & safety guide.
- Local coverage: see the Chattanooga area code guide.
- Worried about spam or robocalls? Browse our Scam Alerts directory.