Area codes · +1
Area code 423
Area code 423 is centred on Chattanooga, Tennessee. We hold 5,926 allocated blocks for it across 75 rate centres, split 48% mobile, 38% landline and 14% VoIP.
The towns inside area code 423
Area code 423 is not a city code. It covers 75 separate rate centres — billing areas, each its own local calling zone. The largest of them are named in the table below.
That matters twice over. A call between two 423 numbers is not necessarily a local call, because they can sit in different rate centres. And a code this wide narrows a subscriber to a region rather than a town.
Tennessee is split across 7 area codes — 423, 615, 901, 865, 931, 731 and others. By allocated blocks 423 is the largest of them, holding 21% of the Tennessee total.
Where 423 numbers are concentrated
NANPA truncates rate-centre names to ten characters and drops the spaces, which is why Johnson Cy and Greenevl are shortened. Names are reproduced as recorded rather than expanded — the abbreviation is the key the block data is filed under.
| Rate centre | Blocks | Share of 423 |
|---|---|---|
| Chattnooga | 1,348 | 23% |
| Johnson Cy | 512 | 9% |
| Bristol | 286 | 5% |
| Cleveland | 275 | 5% |
| Kingsport | 243 | 4% |
| Morristown | 232 | 4% |
| Athens | 227 | 4% |
| Greenevl | 146 | 2% |
| Lafollette | 143 | 2% |
| Newport | 118 | 2% |
| Rogersvl | 114 | 2% |
| Elizabthtn | 106 | 2% |
| Sweetwater | 91 | 2% |
| Charleston | 81 | 1% |
| Benton | 78 | 1% |
| Blountvl | 76 | 1% |
| Bulls Gap | 75 | 1% |
| Soddydaisy | 73 | 1% |
| Erwin | 69 | 1% |
| Madisonvl | 65 | 1% |
| Limestone | 64 | 1% |
| Dayton | 59 | 1% |
| So Pittsbg | 58 | 1% |
| Sneedville | 55 | 1% |
51 further rate centres in 423 hold fewer blocks than these.
Carriers holding the most 423 blocks
Verizon Wireless963 blocks
AT&T Wireless731 blocks
Onvoy706 blocks
Bandwidth440 blocks
Bellsouth Telecomm Inc Dba South Central Bell Tel386 blocks
T-Mobile USA, Inc.238 blocks
The largest holder, Verizon Wireless, has 16% of the code.
These are original allocations. A number keeps its digits and its block when its subscriber moves network, so a ported 423 number still reports the carrier it started with. Closing that gap needs a live query against the routing database. How line type is derived.
Check a single 423 number, or run a whole list through the free cleaner — neither uploads anything.
Common questions
Where is area code 423?
Area code 423 is centred on Chattanooga, Tennessee and spans 75 rate centres, so it covers a region rather than a town.
Is a 423 number a mobile or a landline?
It can be either, and the digits do not say which. North American mobile and landline numbers share the same ranges, so the answer comes from the carrier holding the block. In 423 the split runs 48% mobile, 38% landline and 14% VoIP, so mobile is the most likely single answer.
Which carriers hold 423 numbers?
The largest holders are Verizon Wireless, AT&T Wireless, Onvoy. That is the carrier the block was allocated to, which is not necessarily the network a given number sits on today.
How many 423 numbers are there?
The code holds 5,926 allocated blocks in our copy of the numbering plan. A block is 1,000 or 10,000 consecutive numbers depending on how deeply it has been pooled, so 423 covers on the order of 5,926,000 possible numbers — most of which have never been issued to anyone.