---
title: "Area code 857: Massachusetts, United States"
url: "https://lookvalid.com/area-code/857.md"
canonical_url: "https://lookvalid.com/area-code/857"
last_updated: "2026-10-23"
type: "reference"
summary: "Area code 857 serves Massachusetts, United States. Number formats, numbering rules, a live phone validator and the other codes in Massachusetts."
---

# Area code 857: Massachusetts, United States

Area code 857 serves Massachusetts, United States. Number formats, numbering rules, a live phone validator and the other codes in Massachusetts.

NANPA lists 358 central office codes (prefixes) in use in area code 857, held by 39 holders across 21 rate centers.
The largest rate center is BOSTON, with 150 prefixes (42%).
Verizon Wireless holds the most prefixes, 67 (19%). 99% of the prefixes are pooled, which means their thousands-blocks can belong to different companies.
The FCC unwanted-call data has 1,438 complaints on file for 1,038 numbers in 857, most often filed as "Unwanted Calls". These are consumer reports, not findings.

## Facts

- 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

| 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% |

## Carriers

| 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.

## History

- 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.

## Nearest area codes

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).

## ZIP codes

66 ZIP codes fall in places that have a rate center in this area code. The places with the most are Boston, MA (36 ZIP codes), Cambridge, MA (6 ZIP codes) and Quincy, MA (4 ZIP codes). A ZIP code and an area code are unrelated systems, so a ZIP code can sit in more than one area code and an area code spans many ZIP codes.

## Complaints on file

1,438 complaints for 1,038 numbers. Numbers whose latest complaint falls in each year:

- 2023: 68
- 2024: 74
- 2025: 68

## Questions

### 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.

Sources: NANPA central office code report dated 2026-10-17; NANPA NPA report dated 2026-10-18; FCC unwanted-call complaints, data fetched 2026-10-17; ZIP code places from GeoNames (CC BY 4.0).