Phone numbers in Frankfort, Illinois
Frankfort has 14 phone prefixes in area codes 779, 815.
Biggest holders: AT&T Mobility, AT&T (local phone), Level 3 (Lumen). This is the local calling area (rate center) where those prefixes were first assigned.
- Mobile carrier 21%
- Local phone company 21%
- Internet / business phone carrier 57%
Every prefix in Frankfort
Search the first six digits of a number in this list. If it's here, the number started in Frankfort with the carrier shown. If it isn't, check the Illinois page or look the number up.
| Prefix | Carrier | Type | Assigned |
|---|---|---|---|
| 779-216 | Peerless Network Of Illinois | Internet / business phone carrier | 2013 |
| 779-243 | AT&T Mobility | Mobile carrier | 2017 |
| 779-254 | Comcast | Internet / business phone carrier | 2015 |
| 779-324 | Bandwidth | Internet / business phone carrier | 2010 |
| 779-333 | Onvoy | Internet / business phone carrier | 2013 |
| 779-339 | AT&T Mobility | Mobile carrier | 2021 |
| 779-447 | AT&T Mobility | Mobile carrier | 2026 |
| 779-900 | Fractel | Internet / business phone carrier | 2019 |
| 815-277 | Teleport Communications America | Internet / business phone carrier | – |
| 815-412 | Level 3 (Lumen) | Internet / business phone carrier | – |
| 815-464 | AT&T (local phone) | Local phone company | – |
| 815-469 | AT&T (local phone) | Local phone company | – |
| 815-534 | Level 3 (Lumen) | Internet / business phone carrier | – |
| 815-806 | AT&T (local phone) | Local phone company | – |
Most prefixes are pooled: the 10,000 numbers in each are handed out in blocks of 1,000 to different carriers, and people can also take their numbers to another carrier. So the carrier shown is where the prefix started, not a guarantee about any one number. Source: NANPA central office code records, 2026-10-10.