| District of Massachusetts area codes: 857 | |
|---|---|
| Country | United States |
| State/Province | Massachusetts |
| Major City | Boston |
| Time Zone | Eastern |
| Prefix | County | Primary City | Company |
|---|---|---|---|
| 857-304 | Middlesex | Watertown, MA | Teleport Communications America |
| 857-305 | Suffolk | Boston, MA | Level 3 Enhanced Services |
| 857-307 | Norfolk | Brookline, MA | Verizon New England Inc. |
| 857-312 | Suffolk | Boston, MA | Metro PCS |
| 857-313 | Suffolk | Boston, MA | Omnipoint Miami E License |
| 857-317 | Suffolk | Boston, MA | Centurylink Communications LLC |
| 857-318 | Suffolk | Boston, MA | Allegiance Telecom |
| 857-321 | Suffolk | Boston, MA | Cellco Partnership DBA Verizon Wireless |
| 857-323 | Suffolk | Chelsea, MA | Verizon New England Inc. |
| 857-333 | Suffolk | Boston, MA | Omnipoint Miami E License |
| 857-334 | Suffolk | Boston, MA | Omnipoint Miami E License |
| 857-342 | Suffolk | Hyde Park, MA | Cellco Partnership DBA Verizon Wireless |
| 857-345 | Suffolk | Hyde Park, MA | Cellco Partnership DBA Verizon Wireless |
| 857-350 | Suffolk | Boston, MA | Cellco Partnership DBA Verizon Wireless |
| 857-362 | Suffolk | Boston, MA | Verizon New England Inc. |
| 857-363 | Middlesex | Everett, MA | Cellco Partnership DBA Verizon Wireless |
| 857-364 | Norfolk | Brookline, MA | Broadview Networks |
| 857-366 | Suffolk | Boston, MA | Cellco Partnership DBA Verizon Wireless |
| 857-368 | Suffolk | Boston, MA | Paetec Communications |
| 857-373 | Norfolk | Needham, MA | Broadview Networks |
There are 164 prefixes, In the code area, the major cities are Belmont, MA;Boston, MA;Brookline, MA;Cambridge, MA. The major city is Boston.