Where is area code 857?
NANPA assigns 857 to Massachusetts. The source report does not provide city-level coverage for this record, so this page does not guess a particular city. Browse other codes in Massachusetts
Verified area-code information
857 Area Code
857 is an in-service United States area code assigned to Massachusetts. It identifies a numbering region, not a caller’s current location.
Official Numbering RegionVerified NANPA Assignment
MassachusettsArea Code 857
Country: United States•Time Zone: Eastern•Overlays: 617•In Service: 02-May-2001
- Numbering country
- United States
- Area-code type
- Geographic
- Numbering region
- Massachusetts
- Time-zone information
- Eastern
- In service since
- 02-May-2001
View the official area-code maps ↗. Maps show numbering areas, not a caller’s location.
Time zones associated with 857
NANPA lists Eastern for this numbering area. These are numbering-region time zones, not a caller’s current location.
Eastern time
An area code can span more than one time zone. Local daylight-saving rules may differ.
What area codes overlay 857?
The NANPA source lists 617 in the same overlay complex. An overlay can serve the same broad numbering area; individual numbers still do not prove where a person is.
How do you dial a 857 number?
Use the North American country calling code +1 followed by the three-digit area code and seven-digit local number. For example, write the pattern as +1 857 XXX XXXX. Local dialing rules and charges depend on your location and provider. Check a supported dialing format or check NANPA’s 10-digit dialing list.
Assigned prefixes in 857
NANPA’s US report listed 358 assigned prefixes on 2026-09-29. These are code assignments, not a count of active phone numbers or proof of a caller’s current carrier. Search any US area code and prefix.
Top rate-center labels by assigned prefixes
| Rate center | Assigned prefixes |
|---|---|
| BOSTON | 150 |
| CAMBRIDGE | 27 |
| BROOKLINE | 26 |
| ROXBURY | 20 |
| NEWTON | 18 |
Top listed companies by assigned prefixes
| Assignment company | Assigned prefixes |
|---|---|
| CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MA | 67 |
| OMNIPOINT MIAMI E LICENSE, LLC | 60 |
| ONVOY, LLC - MA | 42 |
| METROPCS, INC. | 25 |
| PAETEC ITEL, LLC | 19 |
857 prefix lookup
358 assigned prefixes are listed for this area code. Search NANPA’s US central-office code assignments. The listed company and rate center describe an assignment; number portability means they cannot identify the current carrier, subscriber, or caller.
The area-code file loads when you search. The three-digit prefix stays in your browser.
Check a number with area code 857
Enter the full ten-digit number to see its structure and formatting. The check stays in your browser.
Check a 857 number
Enter a 10-digit +1 North American number. We check its structure and area-code record, not the caller’s identity or whether the line is active.
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Received an unfamiliar call?
The displayed number may be spoofed. Do not rely on an area code as proof of caller identity. If the caller claims to represent a business, end the call and contact that business using a number you found independently.
Common questions about 857
What time zone is area code 857 in?
857 is assigned to Massachusetts, and the NANPA record associates it with Eastern time. A phone number does not reveal its owner’s current time zone. The clock above uses a representative time zone for the numbering area.
Does 857 mean the caller is in Massachusetts?
No. An area code is an assignment, and a person can travel, move, use internet calling, or display a spoofed number.
Can this page identify who called?
No. OfficialAreaCode has no live subscriber directory or spam-report database.