Area code
857
857 is a United States area code. Under the North American Numbering Plan it belongs to Massachusetts, which has 9 area codes in total.
Validate a number in 857
Paste a full number and the tool checks it against the numbering plan. It returns the standard formats, the line type the plan assigns and the area code region.
Digits with or without punctuation work. Numbers outside the US are read with the +country code.
Area code 857 at a glance
NANPA lists 358 central office codes (prefixes) in use in area code 857, held by 39 holders across 21 rate centers.
| Fact | Value |
|---|---|
| In service since | 2001-05-02 |
| Time zone | Eastern (E) |
| Assigned overlays | 617 (1947-01-01) |
| Prefixes in use | 358 |
| Pooled prefixes | 353 (99%) |
| Rate centers | 21 |
| Companies holding prefixes | 39 |
| Assignment dates on file | 2001-03-19 to 2025-07-10 (333 prefixes) |
| ZIP codes in its places | 66 |
Rate centers in area code 857
The largest rate center is BOSTON, with 150 prefixes (42%).
| Rate center | Prefixes | Share |
|---|---|---|
| BOSTON | 150 | 42% |
| CAMBRIDGE | 27 | 8% |
| BROOKLINE | 26 | 7% |
| ROXBURY | 20 | 6% |
| NEWTON | 18 | 5% |
| QUINCY | 14 | 4% |
| BRIGHTON | 13 | 4% |
| DORCHESTER | 13 | 4% |
| 13 other rate centers | 77 | 22% |
Who holds the prefixes in 857
Verizon Wireless holds the most prefixes, 67 (19%). 99% of the prefixes are pooled, which means their thousands-blocks can belong to different companies.
| Holder | Prefixes | Share |
|---|---|---|
| Verizon Wireless | 67 | 19% |
| Omnipoint Miami E License | 60 | 17% |
| Onvoy | 42 | 12% |
| Metropcs | 25 | 7% |
| Paetec Itel | 19 | 5% |
| New Cingular Wireless PCS | 18 | 5% |
| 33 other carriers | 127 | 35% |
A prefix holder is the company a code was assigned to, not necessarily a number's current carrier, because numbers can be ported to another company. Find which carrier a number is on, or browse the prefix holders.
History of area code 857
- 1947-01-01 Area code 617, named as the parent of 857 in the NANPA report, was in service.
- 2001-05-02 Area code 857 went into service.
Area codes nearest to 857
Distance is measured between the centers of the ZIP code places each area code serves, so it is a rough guide.
Overlay codes in the same area
ZIP codes in area code 857
66 ZIP codes fall in places that have a rate center in this area code.
| Place | ZIP codes |
|---|---|
| Boston, MA | 36 |
| Cambridge, MA | 6 |
| Quincy, MA | 4 |
A ZIP code and an area code are unrelated systems. A ZIP code can sit in more than one area code, and an area code spans many ZIP codes.
Complaints on file for 857 numbers
1,438 FCC complaints are on file for 1,038 numbers in 857, most often filed as "Unwanted Calls". These are unverified consumer reports.
| Year of latest complaint | Numbers |
|---|---|
| 2023 | 68 |
| 2024 | 74 |
| 2025 | 68 |
Other area codes in Massachusetts
Massachusetts is one state with 9 area codes in the NANPA table. 857 is one of them.
Next to 857 in the numbering table
These are the codes just before and after 857 when all are sorted by number. They are neighbours on the list, not necessarily on the map.
What the area code does and does not tell you
A number that starts with 857 was first assigned in Massachusetts. That is a fact about where the number began, and it is a useful hint when you check a form entry, for example a billing address in Massachusetts next to a 857 phone number.
It does not show where the person is today. A number stays with its owner after a move or a change of provider (number portability), and mobile numbers travel with the handset. The area code also cannot tell you whether the line is active, who the carrier is, or whether the number is mobile or fixed: the plan shares those ranges. Read more about the area code, the numbering plan and line type.
Check numbers in bulk with the API
| Product | Credits | Docs |
|---|---|---|
| Phone Numbering-Plan Validation | 1 credit per valid number | API docs |
| Phone Intelligence (carrier and line status) | 1 credit per check (invalid numbers outside the US and Canada are free) | Product page |
Questions about area code 857
Where is area code 857?
NANPA assigns area code 857 to Massachusetts, United States.
In which state does area code 857 sit?
Massachusetts. 857 is one of 9 area codes the NANPA table assigns to the state.
Which places does area code 857 cover?
The places with the most ZIP codes among the rate centers in 857 are Boston, MA, Cambridge, MA and Quincy, MA. The rate center list on this page shows all of them.
Who owns area code 857?
NANPA assigns area codes. Within 857, Verizon Wireless holds the most prefixes, 67 prefixes or 19%.
Which time zone does 857 use?
The NANPA NPA report lists the time zone for 857 as Eastern (E).
What year did 857 enter service?
The NANPA NPA report gives an in-service date of 2001-05-02, so 857 has been in use since 2001.
Does area code 857 have an overlay?
Yes. 617 (in service 1947-01-01) shares the same area with 857, so numbers from all of them are local to each other.
Which area codes are nearest to 857?
The area codes closest to 857, measured between the centers of the ZIP code places they serve, are 781 (about 2 miles), 339 (about 3 miles), 508 (about 19 miles), 351 (about 23 miles) and 978 (about 23 miles).
How many prefixes does area code 857 have?
NANPA's report dated 2026-10-17 lists 358 prefixes in service in 857, spread over 21 rate centers and 39 holders.
Are there complaints about 857 numbers?
The FCC data on file has 1,438 complaints for 1,038 numbers in 857. They are unverified consumer reports. A number with no complaints on file is not proven safe.
Area code assignments: North American Numbering Plan Administrator NPA report, file dated 10/17/2026, retrieved 2026-10-17. Source file. New codes are assigned several times a year. Prefixes, rate centers, holders, time zone, in-service date and overlays: NANPA central office code report dated 2026-10-17 and NPA report dated 2026-10-18. Complaints: FCC consumer complaints open data, fetched 2026-10-17. ZIP code places: Postal code places and coordinates: GeoNames (geonames.org), licensed CC BY 4.0.