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Area code 857

Area code 857 Boston, Massachusetts

Area code 857 is in Massachusetts, with numbers assigned in Boston, Cambridge, Brookline and 9 more places. It’s 12:14 AM there now.

State
Massachusetts9 area codes in Massachusetts
Time zone
Eastern12:14 AM there now
Exchanges
36212 places
Overlay
617Same area, 10-digit dialing
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Where area code 857 is

Numbers in 857 are assigned to 12 places in 3 counties: Suffolk County, Middlesex County and Norfolk County.

Boston holds most of them: 55% of the exchanges.

  • Boston198
  • Cambridge28
  • Brookline27
  • Newton18
  • Quincy14
  • Somerville8
  • Belmont7
  • Winthrop Town6
  • Watertown6
  • Milton4
  • Chelsea4
  • Everett4

Phone companies in 857

362 blocks of numbers in 857 are held by 40 phone companies. The most belong to T-Mobile (86), Verizon Wireless (67) and Inteliquent (42).

A large share, about 43%, belongs to competitive and internet phone carriers; wireless networks hold 48% and local phone and cable companies 9%.

A block’s holder is the company it was first assigned to; numbers can move to other carriers since.

History and overlays

857 went into service in 2001, added to the area of 617.

617 (since 1947) shares the same area, so a new number there can get any of these codes and local calls are dialed with all 10 digits.

71 new exchanges were assigned since 2021, the latest in June 2026.

Calling 857

It’s 12:14 AM Eastern time in 857 right now.

From elsewhere in the U.S., dial 1, 857 and the 7-digit number; inside the area, all 10 digits too.

Nearby area codes

Massachusetts has 9 area codes: 339, 351, 413, 508, 617, 774, 781, 857 and 978.

From the North American Numbering Plan Administrator’s area code and exchange records (10/22/2026) and U.S. Census place and county names. Places and companies are where number blocks were assigned, not where anyone lives or which carrier a number uses today.

Map of the 857 area code

Map of the 857 area code around Boston, Cambridge and Brookline, Massachusetts.

Interactive map © OpenStreetMap contributors

Cities on the map

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Questions about 857

Where is area code 857?

In Massachusetts, covering Boston, Cambridge and Brookline and other places across 3 counties.

What time zone is 857 in?

Eastern time. It was 12:14 AM there when this page loaded.

Is 857 an overlay?

Yes. 617 serves the same area, so dial all 10 digits for local calls.

Which phone companies have 857 numbers?

40 companies hold blocks; the most belong to T-Mobile, Verizon Wireless and Inteliquent. About 48% of blocks are wireless.

Is 857 running out of numbers?

Not on record. 71 new exchanges have been assigned since 2021.