Area codes 617 and 857


Area codes 617 and 857 are the North American area codes serving Boston and several surrounding communities in Massachusetts—such as Brookline, Cambridge, Newton and Quincy.
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.
In July 1988, most of the western and southern portions of the old 617 territory, including Worcester, 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 and western portions of 617 split off as 781, which almost completely surrounds 617. This reduced 617 to Boston itself and its closer-in suburbs—an area 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. On May 2, 2001, 857 was overlaid onto 617. Since then, 10-digit local dialing has been mandatory.
Some mobile phone numbers from the 1990s assigned to communities in the area surrounding 617 kept the 617 area code after the split.

Splits from area code 617

As of 2018, the 617/857 NPA is projected to be exhausted by 2041.

Communities

Portions of the following counties are covered:
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303, 304, 305, 306, 309, 310, 312, 314, 316, 320, 330, 331, 338, 341, 342, 343, 345, 346, 348, 350, 351, 352, 353, 356, 357, 358, 366, 367, 368, 369, 371, 372, 373, 375, 377, 378, 385, 391, 392, 399, 406, 407, 412, 413, 414, 416, 421, 422, 423, 424, 425, 426, 428, 429, 434, 437, 438, 439, 443, 447, 448, 449, 450, 451, 456, 457, 459, 470, 476, 478, 480, 482, 488, 490, 502, 504, 507, 510, 512, 513, 515, 517, 519, 521, 523, 526, 530, 531, 532, 534, 535, 536, 542, 543, 549, 556, 557, 563, 565, 570, 571, 572, 573, 574, 578, 579, 585, 587, 589, 590, 592, 593, 594, 595, 598, 603, 619, 620, 624, 626, 635, 636, 637, 638, 643, 645, 646, 648, 650, 654, 662, 664, 670, 671, 672, 680, 683, 686, 692, 694, 695, 697, 699, 717, 719, 720, 721, 722, 723, 724, 725, 726, 727, 728, 733, 737, 742, 743, 747, 748, 753, 755, 756, 757, 760, 763, 772, 777, 778, 780, 784, 785, 788, 790, 794, 799, 816, 818, 820, 823, 824, 828, 830, 832, 834, 835, 838, 839, 840, 848, 849, 850, 851, 854, 856, 859, 861, 865, 867, 869, 872, 875, 877, 878, 880, 888, 892, 894, 896, 897, 901, 904, 908, 912, 918, 919, 921, 927, 931, 933, 936, 937, 938, 939, 943, 946, 947, 948, 951, 954, 956, 959, 960, 961, 963, 973, 986, 988, 989, 994
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