top of page


area code

Biggest city:





Eastern (GMT -5)

Nearby area codes: 

Zip codes



Major Cities:

Boston metropolitan area


Average Income:





Unemployment Rate:

Area code 857 is a significant component of the telephone numbering plan in the United States, particularly in Massachusetts. Geographical Coverage: Area code 857 serves the Boston metropolitan area and its surrounding communities in Massachusetts. This includes parts of cities such as Boston, Cambridge, Quincy, and Brookline. The area is known for its historical significance, cultural diversity, and as a major educational and economic hub. Introduction as an Overlay Code: The 857 area code was introduced in 2001 as an overlay for the existing 617 area code. The introduction of an overlay code was necessary to address the increasing demand for telephone numbers in the region, driven by the growth in residential and business services, as well as the proliferation of cell phones. Impact on Dialing Patterns: With the introduction of the 857 overlay, 10-digit dialing (area code + phone number) became mandatory for all calls within and between the 617 and 857 area codes. This means that even for local calls within the same area code, the full 10-digit number must be dialed. In conclusion, area code 857 plays a vital role in Massachusetts' telecommunication infrastructure, particularly in the densely populated and active Boston area. Its implementation as an overlay area code reflects the region's expansion and the evolving needs for more telephone numbers, ensuring continuous connectivity for the community.
bottom of page