Area codes · +1
Area code 406
Area code 406 is centred on Billings, Montana. We hold 4,959 allocated blocks for it across 260 rate centres, split 37% mobile, 47% landline and 16% VoIP.
The towns inside area code 406
Area code 406 is not a city code. It covers 260 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 406 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.
406 is the only area code whose numbers sit mainly in Montana. Every Montana number therefore starts 406 unless it was issued in a border rate centre billed to a neighbouring code.
Where 406 numbers are concentrated
Rate-centre names are reproduced as NANPA records them. The agency truncates them to ten characters, so longer names appear shortened elsewhere on this site.
| Rate centre | Blocks | Share of 406 |
|---|---|---|
| Billings | 512 | 10% |
| Missoula | 290 | 6% |
| Helena | 251 | 5% |
| Greatfalls | 238 | 5% |
| Bozeman | 201 | 4% |
| Kalispell | 145 | 3% |
| Butte | 136 | 3% |
| Miles City | 76 | 2% |
| Sidney | 71 | 1% |
| Hamilton | 68 | 1% |
| Hardin | 68 | 1% |
| Livingston | 66 | 1% |
| Lewistown | 65 | 1% |
| Columbus | 64 | 1% |
| Havre | 63 | 1% |
| Laurel | 61 | 1% |
| Libby | 59 | 1% |
| Red Lodge | 57 | 1% |
| Glendive | 56 | 1% |
| Forsyth | 55 | 1% |
| Shelby | 54 | 1% |
| Colstrip | 53 | 1% |
| Anaconda | 49 | 1% |
| Conrad | 45 | 1% |
236 further rate centres in 406 hold fewer blocks than these.
Carriers holding the most 406 blocks
Onvoy898 blocks
Verizon Wireless795 blocks
Qwest Corporation548 blocks
AT&T Wireless419 blocks
Bandwidth178 blocks
Terra Nova Telecom Inc.158 blocks
The largest holder, Onvoy, has 18% of the code.
These are original allocations. A number keeps its digits and its block when its subscriber moves network, so a ported 406 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 406 number, or run a whole list through the free cleaner — neither uploads anything.
Common questions
Where is area code 406?
Area code 406 is centred on Billings, Montana and spans 260 rate centres, so it covers a region rather than a town.
Is a 406 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 406 the split runs 37% mobile, 47% landline and 16% VoIP, so landline is the most likely single answer.
Which carriers hold 406 numbers?
The largest holders are Onvoy, Verizon Wireless, Qwest Corporation. That is the carrier the block was allocated to, which is not necessarily the network a given number sits on today.
How many 406 numbers are there?
The code holds 4,959 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 406 covers on the order of 4,959,000 possible numbers — most of which have never been issued to anyone.