Area code 857: where it is and who calls from it
Area code 857 is in Massachusetts.
East-central Massachusetts, including Boston
| Where | Massachusetts |
|---|---|
| Time zone | Eastern Time ยท local time |
| In service since | 2001 |
| Overlay | Yes, with 617 |
| Prefixes assigned | 362 of 792 possible (46%) |
Overlay: 857 covers the same area as 617. Overlay areas use 10-digit dialing, so a seven-digit number alone won't connect, and neighbors can have different area codes.
Where 857 numbers started
Every prefix is assigned to a rate center, the local calling area it was set up in. These are the biggest in 857, with how many prefixes each has.
Who holds 857 numbers
- Mobile carrier 48%
- Local phone company 4%
- Internet / business phone carrier 42%
- Phone company 6%
| Carrier | Type | Prefixes | Share |
|---|---|---|---|
| Verizon Wireless | Mobile carrier | 67 | 19% |
| T-Mobile (including Sprint) | Mobile carrier | 61 | 17% |
| Onvoy | Internet / business phone carrier | 49 | 14% |
| MetroPCS (T-Mobile) | Mobile carrier | 25 | 7% |
| Windstream (PAETEC) | Internet / business phone carrier | 19 | 5% |
| AT&T Mobility | Mobile carrier | 18 | 5% |
| Verizon (local phone) | Local phone company | 13 | 4% |
| MCImetro (Verizon Business) | Internet / business phone carrier | 13 | 4% |
| Level 3 (Lumen) | Internet / business phone carrier | 10 | 3% |
| Bandwidth | Internet / business phone carrier | 10 | 3% |
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.
States served: Massachusetts.
Other area codes in Massachusetts
339 351 413 508 617 774 781 978
Got a call from 857?
An area code tells you where a number was first assigned, not where the caller is. People keep their numbers when they move, and scammers can fake any number. If you weren't expecting the call, let it go to voicemail.
If the call shows a 857 number that matches the first six digits of your own, that's often neighbor spoofing. Use the box above to check the full number.
Area code facts from the NANPA area code database (updated 10/06/2026); prefixes and carriers from NANPA's central office code records (updated 2026-10-10). Place description adapted from Wikipedia, CC BY-SA 4.0.