---
title: "Area code 406: Montana, United States"
url: "https://lookvalid.com/area-code/406.md"
canonical_url: "https://lookvalid.com/area-code/406"
last_updated: "2026-10-23"
type: "reference"
summary: "Area code 406 serves Montana, United States. Number formats, numbering rules, a live phone validator and the other codes in Montana."
---

# Area code 406: Montana, United States

Area code 406 serves Montana, United States. Number formats, numbering rules, a live phone validator and the other codes in Montana.

NANPA lists 754 central office codes (prefixes) in use in area code 406, held by 63 holders across 260 rate centers.
Qwest holds the most prefixes, 132 (18%). 70% of the prefixes are pooled, which means their thousands-blocks can belong to different companies.
The FCC unwanted-call data has 2,105 complaints on file for 1,735 numbers in 406, most often filed as "Unwanted Calls". These are consumer reports, not findings.

## Facts

- In service since: 1947-01-01
- Time zone: Mountain (M)
- Prefixes in use: 754
- Pooled prefixes: 527 (70%)
- Rate centers: 260
- Companies holding prefixes: 63
- Assignment dates on file: 2001-04-18 to 2026-06-05 (185 prefixes)
- ZIP codes in its places: 241

## Rate centers

| Rate center | Prefixes | Share |
| --- | --- | --- |
| BILLINGS | 72 | 10% |
| MISSOULA | 47 | 6% |
| HELENA | 38 | 5% |
| GREATFALLS | 37 | 5% |
| BOZEMAN | 32 | 4% |
| KALISPELL | 25 | 3% |
| BUTTE | 17 | 2% |
| MILES CITY | 10 | 1% |
| 252 other rate centers | 476 | 63% |

## Carriers

| Holder | Prefixes | Share |
| --- | --- | --- |
| Qwest | 132 | 18% |
| Verizon Wireless | 119 | 16% |
| New Cingular Wireless PCS | 74 | 10% |
| Onvoy | 43 | 6% |
| Triangle Tel. Coop. Assn. | 39 | 5% |
| Nemont Tel Coop | 33 | 4% |
| 57 other carriers | 314 | 42% |

A prefix holder is the company a code was assigned to, not necessarily a number's current carrier, because numbers can be ported to another company.

## History

- 1947-01-01: Area code 406 went into service.

## Nearest area codes

The area codes closest to 406, measured between the centers of the ZIP code places they serve, are 208 (about 302 miles), 986 (about 307 miles), 307 (about 325 miles), 509 (about 405 miles) and 385 (about 433 miles).

## ZIP codes

241 ZIP codes fall in places that have a rate center in this area code. The places with the most are Billings, MT (14 ZIP codes), Helena, MT (8 ZIP codes) and Missoula, MT (8 ZIP codes). A ZIP code and an area code are unrelated systems, so a ZIP code can sit in more than one area code and an area code spans many ZIP codes.

## Complaints on file

2,105 complaints for 1,735 numbers. Numbers whose latest complaint falls in each year:

- 2023: 99
- 2024: 125
- 2025: 126

## Questions

### Where is area code 406?

NANPA assigns area code 406 to Montana, United States.

### In which state does area code 406 sit?

Montana. 406 is one of 1 area code the NANPA table assigns to the state.

### Which places does area code 406 cover?

The places with the most ZIP codes among the rate centers in 406 are Billings, MT, Helena, MT and Missoula, MT. The rate center list on this page shows all of them.

### Who owns area code 406?

NANPA assigns area codes. Within 406, Qwest holds the most prefixes, 132 prefixes or 18%.

### Which time zone does 406 use?

The NANPA NPA report lists the time zone for 406 as Mountain (M).

### What year did 406 enter service?

The NANPA NPA report gives an in-service date of 1947-01-01, so 406 has been in use since 1947.

### Does area code 406 have an overlay?

The NANPA NPA report lists no other area code in an overlay with 406.

### Which area codes are nearest to 406?

The area codes closest to 406, measured between the centers of the ZIP code places they serve, are 208 (about 302 miles), 986 (about 307 miles), 307 (about 325 miles), 509 (about 405 miles) and 385 (about 433 miles).

### How many prefixes does area code 406 have?

NANPA's report dated 2026-10-17 lists 754 prefixes in service in 406, spread over 260 rate centers and 63 holders.

### Are there complaints about 406 numbers?

The FCC data on file has 2,105 complaints for 1,735 numbers in 406. They are unverified consumer reports. A number with no complaints on file is not proven safe.

Sources: NANPA central office code report dated 2026-10-17; NANPA NPA report dated 2026-10-18; FCC unwanted-call complaints, data fetched 2026-10-17; ZIP code places from GeoNames (CC BY 4.0).