Phone numbers in Sandwich, Illinois
Sandwich has 6 phone prefixes in area codes 779, 815.
Biggest holders: Frontier, Peerless Network Of Illinois, Verizon Wireless. This is the local calling area (rate center) where those prefixes were first assigned.
- Mobile carrier 33%
- Local phone company 33%
- Internet / business phone carrier 33%
Every prefix in Sandwich
Search the first six digits of a number in this list. If it's here, the number started in Sandwich with the carrier shown. If it isn't, check the Illinois page or look the number up.
| Prefix | Carrier | Type | Assigned |
|---|---|---|---|
| 779-209 | Peerless Network Of Illinois | Internet / business phone carrier | 2012 |
| 779-706 | Verizon Wireless | Mobile carrier | 2015 |
| 779-931 | Frontier | Local phone company | 2016 |
| 779-978 | UScellular | Mobile carrier | 2015 |
| 815-570 | Level 3 (Lumen) | Internet / business phone carrier | 2002 |
| 815-786 | Frontier | 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.