← Area code 406
406-280 phone numbers
Numbers 406-280-0000 to 406-280-9999 are assigned to New Cingular Wireless PCS, LLC in St. Regis, MT.
Not assigned to any carrier: 406-280-1xxx, 406-280-2xxx, 406-280-3xxx, 406-280-4xxx, 406-280-5xxx, 406-280-6xxx, 406-280-7xxx, 406-280-8xxx, 406-280-9xxx — calls from these use spoofed caller IDs.
Source: North American Numbering Plan Administrator, Nov 3, 2026. Numbers can move between carriers.