Montana has 1 active area code serving the entire state across the Mountain Time Zone. The 406 area code has been Montana’s only telephone code since 1947, making it one of the few states that still operates with a single area code. Whether you need to identify an unknown caller, plan business communications, or understand local dialing requirements, this guide provides complete and current information about Montana’s telephone numbering system.

Key Takeaways

Montana uses only one area code (406) for the entire state
Area code 406 was established in 1947 as one of the original 86 area codes
10-digit dialing became mandatory on October 24, 2021, for all calls in the state
The state operates entirely in the Mountain Time Zone (MST/MDT)
Montana is one of only 11 states that still have a single area code

Quick Reference Table:

Area Code	Primary Cities/Regions	Time Zone	Type	Year Introduced
406	Billings, Missoula, Great Falls, Bozeman, Helena (entire state)	Mountain (MST/MDT)	Original	1947

Area Code 406: Statewide Coverage

Area code 406 was established on January 1, 1947, as part of the original North American Numbering Plan created by AT&T and the Bell System. It was one of 86 original area codes designed to enable direct distance dialing across North America. This state received a single area code due to its sparse population of approximately 560,000 residents at the time and its vast rural landscape spanning over 147,000 square miles.

The middle digit “0” in 406 indicated that the code covered an entire state, a designation system used until 1953. Montana is one of only 15 original area codes that continue to serve an entire state without splits or overlays, sharing this distinction with states like Alaska (907), Delaware (302), Hawaii (808), and Wyoming (307).

Geographic Coverage

Area code 406 covers all 56 counties in that state, from the eastern plains to the western mountains. Major regions include:

Southwest Montana: Yellowstone County, Gallatin County, Madison County
Northwest Montana: Flathead County, Missoula County, Lake County
Central Montana: Cascade County, Lewis and Clark County, Fergus County
Eastern Montana: Custer County, Richland County, Roosevelt County
Northern Border: Toole County, Hill County, Valley County

The code serves a population of approximately 1.1 million residents as of 2024, spread across communities ranging from bustling college towns to remote ranching areas.

Major Cities and Communities

The 406 area code serves the state’s five largest cities and hundreds of smaller communities:

Billings (population ~117,000): Montana’s largest city, major commercial hub
Missoula (population ~73,000): Home to the University of Montana, cultural center
Great Falls (population ~60,000): Historic city along the Missouri River
Bozeman (population ~53,000): Home to Montana State University, a rapidly growing tech hub
Butte (population ~35,000): Historic mining city, strong industrial heritage
Helena (population ~32,000): State capital, government center
Kalispell (population ~24,000): Gateway to Glacier National Park
Havre (population ~9,000): Northern Montana agricultural center
Miles City (population ~8,000): Eastern Montana ranching community
Dillon (population ~4,000): Home to 988 prefix, prompted 10-digit dialing requirement

Evolution and Changes

Unlike most states, Montana has never required an area code split or overlay due to its relatively stable population growth and efficient number management. The Montana Public Service Commission has implemented number pooling strategies to maximize the use of available phone numbers within the 406 area code.

The most significant change came in October 2021 when Montana transitioned to mandatory 10-digit dialing. This change was required because the Federal Communications Commission designated 988 as the new nationwide three-digit number for the National Suicide Prevention Lifeline. Since Montana had existing phone numbers beginning with 988 (particularly in Dillon), all callers had to begin dialing the 406 area code plus the seven-digit number to prevent accidentally dialing the suicide prevention hotline.

Current Usage and Availability

As of 2025, area code 406 has 692 active prefixes serving the state. Approximately 74% of these prefixes are designated for landline use, while 26% serve wireless numbers. The code is not in jeopardy of exhaustion, with sufficient available numbers projected to meet demand until at least 2031 or beyond, thanks to number pooling and efficient resource management.

The state telecommunications are served by approximately 47 carriers, with nearly all supporting local number portability. This allows residents and businesses to keep their phone numbers when switching providers.

What This Means for Residents and Businesses

For Montanans, the 406 area code has become more than just a phone number prefix. It represents state identity and local pride. Many residents celebrate April 6th as “406 Day,” an unofficial holiday honoring Montana. Businesses often prominently display 406 numbers to emphasize their local roots and build trust with customers.

The requirement for 10-digit dialing means that all automated systems, including security alarms, medical monitoring devices, call forwarding settings, and contact lists, must be programmed with the full 10-digit format (406 plus seven-digit number) to function properly.

Understanding Time Zones

Montana operates entirely within the Mountain Time Zone, making it one of the simpler states for time zone management. The entire state observes the same time year-round, with no divisions or exceptions that create confusion for residents or businesses.

UTC Offset and Daylight Saving Time

Montana follows Mountain Standard Time (MST) during the winter months, which is UTC minus 7 hours (UTC-7). During daylight saving time, observed from the second Sunday in March through the first Sunday in November, the state switches to Mountain Daylight Time (MDT), which is UTC minus 6 hours (UTC-6).

All areas of Montana observe daylight saving time, unlike neighboring Arizona, which does not. This means Montana is on the same time as:

Idaho (most of the state)
Wyoming (entire state)
Colorado (entire state)
New Mexico (entire state)
Parts of North Dakota, South Dakota, Nebraska, Kansas, Texas, and Oregon

Scheduling Across Time Zones

When scheduling calls or meetings with people in other regions, remember:

Montana is 2 hours behind Eastern Time (New York, Florida)
Montana is 1 hour behind Central Time (Chicago, Texas)
Montana is 1 hour ahead of Pacific Time (California, Washington)
Montana is 3 hours ahead of Hawaii-Aleutian Time

The uniform time zone throughout Montana simplifies in-state communication, as no time conversions are needed when calling between Billings in the east and Kalispell in the west.

Montana Cities Which Operates Using Area Codes 406

Largest Cities by Population

Billings
- Montana’s largest city and commercial center
- Population: ~117,000
- Major industries: healthcare, energy, transportation
Missoula
- Home to the University of Montana
- Population: ~73,000
- Cultural and educational hub
Great Falls
- Historic Missouri River city
- Population: ~60,000
- Military and healthcare center (Malmstrom Air Force Base)
Bozeman
- Fastest-growing Montana city
- Population: ~53,000
- Tech industry and tourism hub
Butte
- Historic mining city
- Population: ~35,000
- Rich industrial heritage
Helena
- State capital
- Population: ~32,000
- Government and services center
Kalispell
- Gateway to Glacier National Park
- Population: ~24,000
- Tourism and outdoor recreation
Havre
- Northern Montana hub
- Population: ~9,000
- Agriculture and transportation
Anaconda
- Historic smelter town
- Population: ~9,000
- Mining history
Miles City
- Eastern Montana Center
- Population: ~8,000
- Ranching and agriculture

How to Use Area Codes in Montana

Local Calling Requirements

Since October 24, 2021, all calls within Montana require 10-digit dialing. This means you must dial the 406 area code plus the seven-digit phone number for every call, even when calling your next-door neighbor. Seven-digit dialing is no longer functional anywhere in the state.

Local calls remain local for billing purposes. Adding the area code does not convert a local call into a long-distance call or add charges.

Calling Within Montana

To make a local call within Montana:

Dial 406
Dial the seven-digit phone number
Press call

Example: To call 555-1234 in Billings from anywhere in Montana, dial 406-555-1234

You do not need to dial “1” before the area code for local calls. The “1” prefix is only required for long-distance calls outside the state.

Calling from Outside

When calling Montana from another state or Canadian province:

Dial 1 (long-distance prefix)
Dial 406 (Montana area code)
Dial the seven-digit phone number

Example: From New York calling Montana number 555-1234, dial 1-406-555-1234

International Dialing to Montana

For international callers dialing Montana from outside North America:

Dial your country’s international exit code (often 00 or 011)
Dial 1 (country code for the United States)
Dial 406 (Montana area code)
Dial the seven-digit phone number

Example: From the UK calling Montana, dial 00-1-406-555-1234

Emergency and Special Services

Important numbers that do NOT require the area code:

911: Emergency services (police, fire, ambulance)
988: National Suicide Prevention and Crisis Lifeline (active since July 2022)
211: Community services and information
311: Non-emergency municipal services (where available)
411: Directory assistance
511: Travel and road condition information
611: Wireless carrier customer service
811: Call before you dig utility locator service

These three-digit codes work throughout Montana without dialing 406.

Mobile and Landline Considerations

Montana’s 406 area code serves both landline and wireless numbers, with no distinction in the area code itself. Mobile phones follow the same 10-digit dialing requirements as landlines. Number portability allows customers to keep their 406 numbers when:

Moving between cities within the state
Switching from landline to wireless service
Changing service providers

Most carriers in Montana support local number portability, with only two small rural providers (Hot Springs Telephone Company and Northern Telephone Cooperative) as exceptions.

Updating Automated Systems

All automated dialing systems must be programmed with 10-digit numbers. This includes:

Contact lists in mobile phones
Speed dial settings
Call forwarding configurations
Security alarm systems
Fire alarm systems
Medical alert devices
Fax machines
Voicemail systems
Auto-dialers

Failure to update these systems to include the 406 prefix may result in failed calls or incorrect connections.

Summary

Montana’s telecommunications system is straightforward with its single 406 area code serving the entire state since 1947. As one of only 11 states maintaining a single area code, Montana benefits from simplified dialing and a strong local identity. The transition to mandatory 10-digit dialing in October 2021 represents the most significant change in decades, implemented to accommodate the national 988 suicide prevention lifeline.

Operating entirely within the Mountain Time Zone, this state offers uncomplicated scheduling for in-state communications. Current projections show the 406 area code will remain sufficient through 2031 and beyond, ensuring Montana’s iconic single area code legacy continues.

Additional Resources

Official Telecommunications Resources:

Montana Public Service Commission: psc.mt.gov
North American Numbering Plan Administration: nationalnanpa.com
Federal Communications Commission: fcc.gov

Time Zone Information:

National Institute of Standards and Technology Time: time.gov
World Time Zones: timeanddate.com

Related State Pages:

Emergency Services:

National Suicide Prevention Lifeline: Dial 988 or 1-800-273-8255
Emergency Services: Dial 911
Montana 511 Travel Information: Dial 511 or visit mdt511.com