← Area code 309
309-856 phone numbers
Numbers 309-856-0000 to 309-856-9999 are assigned to Frontier North, Inc. in Kewanee, IL. 2 of its ten thousand-number blocks are assigned to other carriers (number pooling).
Not assigned to any carrier: 309-856-2xxx, 309-856-3xxx, 309-856-4xxx, 309-856-9xxx — calls from these use spoofed caller IDs.
Source: North American Numbering Plan Administrator, Nov 3, 2026. Numbers can move between carriers.