857 Area Code — Massachusetts
857 is a North American Numbering Plan area code for Massachusetts, the United States. It covers about 1,235,067 people in 30 towns and 80 ZIP codes, including Boston, Cambridge and Quincy.
| Field | Value |
|---|---|
| Area code | 857 |
| Country | United States (+1) |
| State / province | Massachusetts |
| Type | Shares its towns with 617 |
| Time zone | Eastern |
| Population covered | 1,235,067 |
| Towns covered | 30 |
| ZIP codes | 80 |
| Approx. centre | 42.343, -71.076 |
Where area code 857 is used
Area code 857 is assigned to Massachusetts, the United States, inside the North American Numbering Plan. Numbers in the code are written (857) NXX-XXXX at home and +1 857 NXX-XXXX when dialled from outside Canada and the United States. Since the NANP moved to 10-digit dialling you must always include the area code, even for a local call.
Other area codes in this footprint: 617. They serve towns in the same territory, so a single street can contain numbers from more than one code. That is normal in the NANP and does not change how you dial.
Towns and cities in area code 857
The 30 towns below are the largest in the 857 footprint, ranked by population. Every one of them links to its own page with the full list of area codes and ZIP codes for that town.
| Town | County | Population | ZIP codes |
|---|---|---|---|
| Boston | Suffolk County | 234,424 | 36 |
| Cambridge | Middlesex County | 119,000 | 6 |
| Quincy | Norfolk County | 101,966 | 4 |
| Dorchester | Suffolk County | 86,181 | 3 |
| Somerville | Middlesex County | 78,456 | 3 |
| Dorchester Center | Suffolk County | 56,216 | 1 |
| Brookline | Norfolk County | 53,870 | 2 |
| Everett | Middlesex County | 50,045 | 1 |
| Brighton | Suffolk County | 43,149 | 1 |
| Jamaica Plain | Suffolk County | 40,055 | 1 |
| Chelsea | Suffolk County | 39,908 | 1 |
| Hyde Park | Suffolk County | 37,265 | 1 |
Counties covered
| County | ZIP codes |
|---|---|
| Suffolk County | 51 |
| Middlesex County | 19 |
| Norfolk County | 10 |
Other area codes serving the same towns
Nearby area codes
How to dial area code 857
- Within North America: 857 + 7-digit number (857-NXX-XXXX). The leading 1 is optional on a mobile phone and required on most landlines for long-distance.
- From abroad: your country's international prefix, then 1, then 857, then the 7-digit number — for example 00 1 857 NXX-XXXX from most of Europe.
Frequently asked questions
What area code is 857?
857 is a North American Numbering Plan area code assigned to Massachusetts, the United States. It covers about 1,235,067 people in 30 towns.
Is 857 a US or Canadian area code?
857 is a United States area code. Canada and the United States share the +1 country code, so both are part of the same numbering plan.
What time zone is area code 857 in?
Area code 857 is in the Eastern time zone.
Do I have to dial 10 digits?
Yes. Every NANP call now requires the area code plus the seven-digit number, even for a local call.