423 Area Code — Tennessee
423 is a North American Numbering Plan area code for Tennessee, the United States. It covers about 1,424,610 people in 126 towns and 172 ZIP codes, including Chattanooga, Johnson City and Cleveland.
| Field | Value |
|---|---|
| Area code | 423 |
| Country | United States (+1) |
| State / province | Tennessee |
| Type | Standalone (no other NANP code covers the same towns) |
| Time zone | Eastern and Central |
| Population covered | 1,424,610 |
| Towns covered | 126 |
| ZIP codes | 172 |
| Approx. centre | 35.836, -83.936 |
Where area code 423 is used
Area code 423 is assigned to Tennessee, the United States, inside the North American Numbering Plan. Numbers in the code are written (423) NXX-XXXX at home and +1 423 NXX-XXXX when dialled from outside Canada and the United States. Since the NANP moved to 10-digit dialling you must always include the area code, even for a local call.
Towns and cities in area code 423
The 126 towns below are the largest in the 423 footprint, ranked by population. Every one of them links to its own page with the full list of area codes and ZIP codes for that town.
| Town | County | Population | ZIP codes |
|---|---|---|---|
| Chattanooga | Hamilton County | 214,646 | 20 |
| Johnson City | Washington County | 102,693 | 6 |
| Cleveland | Bradley County | 99,337 | 5 |
| Kingsport | Sullivan County | 88,234 | 6 |
| Morristown | Hamblen County | 53,527 | 4 |
| Greeneville | Greene County | 45,638 | 3 |
| Hixson | Hamilton County | 45,101 | 1 |
| Ooltewah | Hamilton County | 42,093 | 1 |
| Bristol | Sullivan County | 38,494 | 3 |
| Elizabethton | Carter County | 34,120 | 2 |
| Soddy Daisy | Hamilton County | 29,430 | 2 |
| Jonesborough | Washington County | 29,080 | 1 |
Counties covered
| County | ZIP codes |
|---|---|
| Hamilton County | 32 |
| Sullivan County | 13 |
| Washington County | 11 |
| Polk County | 10 |
| Claiborne County | 10 |
| Greene County | 8 |
| McMinn County | 7 |
| Bradley County | 7 |
| Marion County | 7 |
| Morgan County | 7 |
| Hamblen County | 7 |
| Hawkins County | 6 |
Nearby area codes
How to dial area code 423
- Within North America: 423 + 7-digit number (423-NXX-XXXX). The leading 1 is optional on a mobile phone and required on most landlines for long-distance.
- From abroad: your country's international prefix, then 1, then 423, then the 7-digit number — for example 00 1 423 NXX-XXXX from most of Europe.
Frequently asked questions
What area code is 423?
423 is a North American Numbering Plan area code assigned to Tennessee, the United States. It covers about 1,424,610 people in 126 towns.
Is 423 a US or Canadian area code?
423 is a United States area code. Canada and the United States share the +1 country code, so both are part of the same numbering plan.
What time zone is area code 423 in?
Area code 423 is in the Eastern and Central time zone.
Do I have to dial 10 digits?
Yes. Every NANP call now requires the area code plus the seven-digit number, even for a local call.