Area codes 617 and 857 are the area codes serving Boston and several surrounding communities in Massachusetts—such as Brookline, Cambridge, Newton and Quincy (LATA code 128). The main area code, 617, was one of the original area codes from October 1947, and originally covered the eastern two-thirds of Massachusetts, from roughly the western end of Worcester County to Cape Cod and the South Coast. Some mobile phone numbers from the 1990s assigned to communities in the area surrounding 617 (now the 781 area code) kept the 617 area code just on those mobile lines after it split.