Phone numbers in Belmont, Massachusetts
Belmont has 17 phone prefixes in area codes 617, 857.
Biggest holders: Verizon (local phone), MCImetro (Verizon Business), Onvoy. This is the local calling area (rate center) where those prefixes were first assigned.
- Local phone company 35%
- Internet / business phone carrier 53%
- Phone company 12%
Every prefix in Belmont
Search the first six digits of a number in this list. If it's here, the number started in Belmont with the carrier shown. If it isn't, check the Massachusetts page or look the number up.
| Prefix | Carrier | Type | Assigned |
|---|---|---|---|
| 617-209 | Rcn Telecom Services | Phone company | – |
| 617-484 | Verizon (local phone) | Local phone company | – |
| 617-486 | Verizon (local phone) | Local phone company | – |
| 617-489 | Verizon (local phone) | Local phone company | – |
| 617-826 | Level 3 (Lumen) | Internet / business phone carrier | – |
| 617-855 | Verizon (local phone) | Local phone company | – |
| 617-883 | Verizon (local phone) | Local phone company | – |
| 617-932 | Tc Systems | Phone company | – |
| 617-977 | MCImetro (Verizon Business) | Internet / business phone carrier | – |
| 617-993 | Verizon (local phone) | Local phone company | – |
| 857-299 | Onvoy | Internet / business phone carrier | – |
| 857-341 | Bandwidth | Internet / business phone carrier | 2019 |
| 857-373 | Windstream (PAETEC) | Internet / business phone carrier | 2001 |
| 857-394 | MCImetro (Verizon Business) | Internet / business phone carrier | 2021 |
| 857-550 | Commio | Internet / business phone carrier | 2023 |
| 857-626 | MCImetro (Verizon Business) | Internet / business phone carrier | 2001 |
| 857-678 | Onvoy | Internet / business phone carrier | 2021 |
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.