← Area code 406
406-343 phone numbers
Numbers 406-343-0000 to 406-343-9999 are assigned to Project Tel. Co., Inc. in Wyola, MT. 1 of its ten thousand-number blocks are assigned to other carriers (number pooling).
Not assigned to any carrier: 406-343-1xxx, 406-343-4xxx — calls from these use spoofed caller IDs.
Source: North American Numbering Plan Administrator, Nov 3, 2026. Numbers can move between carriers.