NumberingData
Verified Nov 1, 2026 · Source: NANPA CO Code Assignment Records

BIGFORK prefixes in area code 406

NANPA records 3 assigned NXX blocks to rate center BIGFORK in area code 406, 0.4% of the 754 blocks assigned in the code. A rate center is the billing geography a block is allocated to – NANPA truncates the name to ten characters, so read it as a NANPA label rather than a town. 3 holders hold those blocks, the largest being CHARTER IP ENABLED SERVICES, LLC (1), ONVOY, LLC - MT (1), CENTURYTEL OF MONTANA, INC. DBA CENTURYLINK (1). The earliest assignment on record here is 2006-02-28 and the most recent 2020-10-13. 3 of them are in thousands-block pooling, so those prefixes are shared between carriers in 1,000-number lots. The same rate center name also appears in area code 218 – overlay codes cover the same geography, so a rate center is served by all of them.

3 assigned blocks – 0.4% of 406
3 holders of record
3 of them pooled in 1,000-number lots

Prefixes assigned here

PrefixHolder of recordAssignedPooledIn service
406-420 Charter CHARTER IP ENABLED SERVICES, LLC 2006-02-28 yes yes
406-614 Onvoy ONVOY, LLC - MT 2020-10-13 yes yes
406-837 Lumen CENTURYTEL OF MONTANA, INC. DBA CENTURYLINK – yes yes

The holder is who received the block from the numbering administrator. It is not necessarily the carrier serving a given number: numbers move with their owners, and a pooled block is shared.

Who holds the blocks

HolderBrandBlocksShare here
CHARTER IP ENABLED SERVICES, LLC Charter 1 33.3%
ONVOY, LLC - MT Onvoy 1 33.3%
CENTURYTEL OF MONTANA, INC. DBA CENTURYLINK Lumen 1 33.3%

Frequently asked

Which prefixes belong to BIGFORK in area code 406?

3 blocks: 420, 614, 837. The table above gives the holder of each.

Which carriers have numbers in BIGFORK?

CHARTER IP ENABLED SERVICES, LLC (1 block), ONVOY, LLC - MT (1 block), CENTURYTEL OF MONTANA, INC. DBA CENTURYLINK (1 block). These are the holders on record; the carrier actually serving a given number can differ, because numbers move with their owners.

Is BIGFORK a city?

It is a rate center – the unit NANPA allocates number blocks to. Its name is abbreviated to ten characters and is not necessarily a settlement: we print it as recorded rather than guess at the full name.

Other rate centers in 406

All 754 prefixes in 406