Prefix 617-256 — Cambridge, MA

NANPA CO code assignment, current as of July 28, 2026.

Area code
617
Prefix (NXX)
256
Rate center
Cambridge
State
Massachusetts
Time zone
Eastern
Code holder
OMNIPOINT MIAMI E LICENSE, LLC
OCN
6889
Pooled
Yes (thousands-block pooling)
LATA
128

The 617-256 prefix belongs to area code 617 and is anchored to the Cambridge rate center (MA). In NANP terms, the prefix — or NXX — determines the rate center a number is billed against.

Cambridge is part of the Boston-Cambridge-Newton, MA-NH Metropolitan Statistical Area. For routing purposes it sits in LATA 128. Numbers here keep Eastern time.

The assigned code holder is OMNIPOINT MIAMI E LICENSE, LLC, operating company number 6889. This is a pooled prefix — expect numbers within it to be split across more than one carrier in 1,000-number blocks.

Caller ID showing 617-256 is not proof the call came from Cambridge: spoofing and porting both detach numbers from their origin. To verify a caller, hang up and dial the organization's published number, and report suspicious calls to the FTC.

Neighboring prefixes

Prefixes adjacent to 617-256
PrefixRate centerCode holder
617-253 Cambridge VERIZON NEW ENGLAND INC.
617-254 Brighton VERIZON NEW ENGLAND INC.
617-255 Boston VERIZON NEW ENGLAND INC.
617-257 Saugus NEW CINGULAR WIRELESS PCS, LLC - DC
617-258 Cambridge VERIZON NEW ENGLAND INC.
617-259 Boston OMNIPOINT MIAMI E LICENSE, LLC

FAQ

Where is 617-256 located?

The prefix is assigned to the Cambridge rate center in MA, area code 617. It is part of the Boston-Cambridge-Newton, MA-NH Metropolitan Statistical Area.

Which company owns 617-256 numbers?

OMNIPOINT MIAMI E LICENSE, LLC holds the code, but the prefix is pooled — individual thousands-blocks can be assigned to other carriers, and numbers may be ported to any provider.

Is a call from 617-256 safe to answer?

The prefix itself says nothing about the caller. Legitimate Cambridge businesses and spoofed robocalls can both display it. Never share personal data with an unverified inbound caller.