423 Area CodeChattanooga, TN
Area code 423 covers Chattanooga and nearby communities in Tennessee, home to about 795,000 people across 109 cities. It overlays 729 and 865, so the region uses several codes and every local call needs all ten digits.
Overview
- Major City
- Chattanooga
- State
- Tennessee (TN)
- Timezone
- Eastern / Central
- Current Time
- Overlay
- Yes – shares area with 729, 865
Overview of the 423 Area Code
What is the 423 area code?
The 423 area code serves Chattanooga, Tennessee, alongside other established area codes. When you see a 423 number, it indicates a local number within this geographic area.
Why was area code 423 created?
The 423 area code was introduced as an overlay to add numbers in Chattanooga once the existing area codes 729 and 865 began to run out of available prefixes. It added a new supply of numbers without requiring current residents to change their existing digits.
Geographic Coverage of the 423 Area Code
The 423 area code serves Chattanooga and surrounding areas in Tennessee. It operates within the Eastern / Central time zone. It complements the coverage of area codes 729 and 865. This area code covers several key cities, including:
- Chattanooga
- Johnson City
- Kingsport
- Cleveland
- Morristown
- Bristol
Got a call from a 423 number? It came from Chattanooga, TN. Since 423 overlays with 729 and 865, every local call in the region needs all ten digits to land on the right line. Inside 423, Chattanooga holds about 24% of the population; the rest is split across 108 smaller cities.
Chattanooga Area Codes Overview
Chattanooga is served by multiple area codes, reflecting its telecommunications needs. The 423 area code operates alongside 729, 865. Here are the area codes serving this region:
The introduction of the 423 area code helped prevent number exhaustion, ensuring a continuous supply of phone numbers across the geographic area.
What cities does area code 423 cover?
| City | State | Population | % of Area Code | % of City |
|---|---|---|---|---|
| Chattanooga | TN | 191,496 | 1% | 100% |
| Johnson City | TN | 73,635 | 0% | 100% |
| Kingsport | TN | 57,109 | 1% | 100% |
| Cleveland | TN | 50,232 | 0% | 100% |
| Morristown | TN | 32,994 | 0% | 99% |
| Bristol | TN | 27,867 | 0% | 100% |
| East Ridge | TN | 21,970 | 0% | 100% |
| Greeneville | TN | 15,979 | 0% | 100% |
| Athens | TN | 15,050 | 0% | 100% |
| Elizabethton | TN | 14,461 | 0% | 100% |
* Sources: Population – U.S. Census Bureau PEP, Vintage 2024 (SUB-IP-EST2024-POP). Area code assignments – NANPA CO Code data. See our data methodology.
Has area code 423 been reported for unwanted calls?
Yes – 803 unwanted-call complaints were reported to the FTC for numbers showing a 423 area code (May 29 – Jul 2, 2026).
- 59% robocalls
- ↑ 18% vs prior period
Most-reported subjects
- Other44%352
- Medical & prescriptions23%181
- Calls pretending to be government, businesses, or family and friends9%69
* Caller ID is easily spoofed, so these figures reflect the number shown on caller ID, not the caller's true location – an area code alone never identifies a caller. The FTC does not verify the facts in these complaints. Source: FTC Do Not Call (DNC) Reported Calls Data, retrieved 2026-07-05.
Which prefixes and exchanges belong to area code 423?
72% assigned to a telco
- 70% Landline
- 30% Wireless
- 0% Unknown
| Prefix | Usage | Carrier |
|---|---|---|
| (423)200- | Landline | Level 3 Communications |
| (423)201- | Landline | Level 3 Communications |
| (423)202- | Landline | Mcimetro Access Transmission Services |
| (423)203- | Wireless | Dish Wireless |
| (423)205- | Landline | Onvoy |
| (423)206- | Landline | Rclec |
| (423)207- | Landline | Level 3 Communications |
| (423)208- | Wireless | New Cingular Wireless Pcs |
| (423)209- | Landline | South Central Bell Tel |
| (423)210- | Wireless | United States Cellular |
Frequently Asked Questions about the 423 Area Code
Who called me from a 423 number?
A 423 number is assigned to Chattanooga, Tennessee, so a call may come from there. But caller ID is easy to fake, and scammers often spoof a local 423 code to look nearby, so a 423 number doesn't prove the caller is local. Recently, 803 unwanted-call complaints were reported to the FTC for numbers showing the 423 code (59% flagged as robocalls). If you don't recognize the number, let it go to voicemail; a real caller will leave a message.
Is 423 a scam area code?
No area code is a scam on its own. 423 is a normal, officially assigned code for Chattanooga, Tennessee. Spam callers spoof local codes to raise the odds you answer, so 423 on your caller ID says nothing about who is really calling. Recently, 803 unwanted-call complaints were reported to the FTC for numbers showing the 423 code (59% flagged as robocalls). Judge the call itself, not the area code.
Why do I keep getting calls from the 423 area code?
Repeated calls from different 423 numbers are usually spoofing: a robocaller rotates through 423 numbers so each call looks local and slips past simple blocks. Recently, 803 unwanted-call complaints were reported to the FTC for numbers showing the 423 code (59% flagged as robocalls). Blocking one number rarely helps; voicemail screening, your carrier spam filter, and the Do Not Call Registry work better.
Should I answer an unknown 423 number?
If you aren't expecting a 423 call, let it ring to voicemail. Legitimate callers leave a message, most robocallers hang up when no one picks up, and answering can mark your number as active and bring more calls.
How do I block calls from the 423 area code?
Block a single 423 number from your recent-calls list (iPhone: tap the number, then Block this Caller; Android: tap the number, then Block or report spam). To cut the volume, turn on Silence Unknown Callers on iPhone or spam protection on Android, enable spam filtering from your carrier, and register at DoNotCall.gov. Blocking the entire 423 code also stops legitimate local calls, so use it only as a last resort.
Where is area code 423?
Area code 423 covers Chattanooga and the surrounding area in Tennessee, spanning 109 cities with about 795,194 residents. It shares its area with overlay codes 729, 865.
Is 423 a real area code?
Yes. 423 is an active code in the North American Numbering Plan, assigned by NANPA and in service for Chattanooga, Tennessee. A real code can still show up on spoofed spam calls, so treat unknown 423 calls with normal caution.
What timezone is the 423 area code in?
The 423 area code is in the Eastern / Central. Because a number can be kept when someone moves or switches to VoIP, a specific 423 caller may not be in that zone.
How do I call a 423 number from abroad?
From outside the US, dial your country's exit code, then 1 (the US country code), then 423 and the seven-digit number. From a mobile phone you can usually just enter +1 423 followed by the number and let the phone add the exit code for you.