Area code 617 covers the city of Boston and its closest inner suburbs in eastern Massachusetts, including Cambridge (home to Harvard and MIT), Brookline, Newton, Quincy, Somerville, and Chelsea, forming one of the more compact numbering areas in New England compared to codes covering wider swaths of a state. It was created in October 1947 as one of the original 86 North American area codes and originally spanned the eastern two-thirds of Massachusetts out to Worcester County and Cape Cod; a July 1988 split carved off those outer regions into what eventually became the 774 overlay territory, and a further 1997 split created area code 781, which nearly encircled Boston and narrowed 617 to its present footprint. As the reduced territory kept filling up, regulators introduced 857 as an all-services overlay covering the same footprint, effective May 2, 2001, meaning a Boston-area number today could be issued as either 617 or 857 and mandatory 10-digit dialing applies throughout the region. The code runs on Eastern Time, observing EST and EDT. Because 617 is one of the oldest, most recognized codes in the country, it is a common target for caller ID spoofing, including government-impersonation calls claiming to be from the IRS or Social Security Administration, one-ring Wangiri callback schemes, fake university or financial-aid scams that prey on Boston's large student population over loans and tuition refunds, and neighbor spoofing that mimics a victim's own prefix; the recommended response is never to share financial details over such calls and to report them to the FTC. Businesses wanting a local Boston presence can obtain a 617 number through a provider like Softtop by searching Massachusetts inventory, assigning the number to a team or AI receptionist, and porting an existing number in five to ten business days if switching providers.