← Area code 217
217-399 phone numbers
Numbers 217-399-0000 to 217-399-9999 are assigned to Mediacom Telephony of Illinois, LLC in Kincaid, IL. 3 of its ten thousand-number blocks are assigned to other carriers (number pooling).
Not assigned to any carrier: 217-399-2xxx, 217-399-4xxx, 217-399-5xxx, 217-399-6xxx, 217-399-7xxx, 217-399-8xxx — calls from these use spoofed caller IDs.
Source: North American Numbering Plan Administrator, Nov 3, 2026. Numbers can move between carriers.