In July 1988, most of the western, northern, and southern portions of the old 617 territory, including Worcester County, the Merrimack Valley, the South Coast, and the Cape and Islands, were split off as area code 508. Permissive dialing of 617 continued across eastern Massachusetts until January 1, 1989.
In 1997, the northern, western and southern portions of the new 617 split off as 781, which almost completely surrounds 617. This made 617 largely coextensive with the inner ring of Greater Boston.
This was intended as a long-term solution, but within three years 617 was close to exhaustion once again due to the demand for more phone lines for auxiliary devices (mobile phones, fax machines, pagers, and BBS lines). On May 2, 2001, 857 was overlaid onto 617. Since then, 10-digit local dialing has been mandatory.
Some mobile telephone numbers from the 1990s assigned to communities in the area surrounding 617 (which is now the 781 area code) kept the 617 area code after the split.
Area code 508 was split from 617 on July 16, 1988. Area code 978 subsequently split from 508 on September 1, 1997.
Area code 781 was split from 617 on September 1, 1997.
As of 2018, the 617/857 NPA is projected to be exhausted by 2041.[1]
Service areaedit
The numbering plan area 617/857 includes portions of the following counties:
^Staff writer (2023). "Area Code 617/857 map and data profile". Zipdatamaps. Retrieved January 12, 2023.
^Staff writer (2016). "Central Office Code information". Directory-Assistance.net. Archived from the original on June 30, 2011. Retrieved January 12, 2023.
^Staff writer (2009). "617 Area Code exchanges". areacodedownload.com. Archived from the original on February 8, 2009. Retrieved January 12, 2023.
^Operational Services Brief: 311 in Massachusetts, Edward J. Collins Center for Public Management Publications, 10-24-2008
Massachusetts Area Code Map, Mass. Department of Telecommunications and Cable
NANP Administrator (July 2, 1987). "Split of the 617 Numbering Plan Area (NPA)" (PDF). www.nationalnanpa.com. IL-87/07-003. NANP Administrator. Retrieved January 11, 2023. Provides notification of date for the split of the 617 NPA and introduction of the new 508 NPA in Massachusetts.{{cite web}}: CS1 maint: date and year (link)
Staff writer (2023) [2005]. "Area Code 617 map and data profile". Area-Codes.com. Retrieved January 12, 2023. Area Code 617 Demographic Information
"Local Calling Guide". localcallingguide.com. 2023. Retrieved January 12, 2023.
Staff writer (2023). "Area Code, Exchange, Telco, Switch info in 617". telcodata.us. Retrieved January 12, 2023.