All assignees
382 prefixes in 857 · initial assignments from the NANPA CO code file, 09/17/2026
| NPA-NXX | Rate center | OCN | Assigned | Pooled |
|---|---|---|---|---|
| 857-300 | BOSTON | 6387 | 2010-10-08 | Yes |
| 857-301 | BOSTON | 6387 | 2012-12-06 | Yes |
| 857-302 | BOSTON | 428H | 2014-08-04 | Yes |
| 857-303 | BOSTON | 6387 | 2012-11-08 | Yes |
| 857-304 | WATERTOWN | 7135 | 2013-03-13 | Yes |
| 857-305 | BOSTON | 4018 | 2013-07-19 | Yes |
| 857-306 | BOSTON | 508J | 2017-10-17 | Yes |
| 857-307 | BROOKLINE | 9102 | 2006-02-10 | Yes |
| 857-308 | ROXBURY | 6889 | 2014-09-16 | Yes |
| 857-309 | DORCHESTER | 892D | 2014-12-16 | Yes |
| 857-310 | BOSTON | 6889 | 2014-10-14 | Yes |
| 857-311 | XXXXXXXXXX | MULT | — | — |
| 857-312 | BOSTON | 5562 | 2008-08-04 | Yes |
| 857-313 | BOSTON | 6889 | 2012-10-23 | Yes |
| 857-314 | MILTON | 990E | 2015-01-28 | Yes |
| 857-315 | BOSTON | 508J | 2017-10-17 | Yes |
| 857-316 | BRIGHTON | 6889 | 2015-02-27 | Yes |
| 857-317 | BOSTON | 508J | 2013-03-07 | Yes |
| 857-318 | BOSTON | 7229 | 2007-10-17 | Yes |
| 857-319 | BOSTON | 6387 | 2015-06-04 | Yes |
| 857-320 | CAMBRIDGE | 6889 | 2014-10-14 | Yes |
| 857-321 | BOSTON | 6387 | 2011-03-10 | Yes |
| 857-322 | EASTBOSTON | 318J | 2017-10-27 | Yes |
| 857-323 | CHELSEA | 9102 | 2013-01-22 | Yes |
| 857-324 | BOSTON | 6387 | 2017-12-06 | Yes |
| 857-325 | NEWTON | 6387 | 2015-03-31 | Yes |
| 857-326 | BOSTON | 6387 | 2017-12-06 | Yes |
| 857-327 | BOSTON | 6387 | 2015-02-02 | Yes |
| 857-328 | BOSTON | 597F | 2019-06-25 | Yes |
| 857-329 | BOSTON | 6387 | 2017-12-29 | Yes |
| 857-330 | BOSTON | 6387 | 2014-10-01 | Yes |
| 857-331 | CAMBRIDGE | 6387 | 2015-07-22 | Yes |
| 857-332 | BOSTON | 6387 | 2018-01-15 | Yes |
| 857-333 | BOSTON | 6889 | 2010-11-09 | Yes |
| 857-334 | BOSTON | 6889 | 2006-09-20 | Yes |
| 857-335 | BOSTON | 425J | 2019-06-06 | Yes |
| 857-336 | WINTHROP | 892D | 2016-03-01 | Yes |
| 857-337 | BROOKLINE | 6387 | 2015-10-07 | Yes |
| 857-338 | BOSTON | 7135 | 2018-01-25 | Yes |
| 857-339 | ROXBURY | 939H | 2024-02-09 | Yes |
| 857-340 | BROOKLINE | 6889 | 2020-09-29 | Yes |
| 857-341 | BELMONT | 990E | 2019-02-07 | Yes |
| 857-342 | HYDE PARK | 6387 | 2007-08-08 | Yes |
| 857-343 | BOSTON | 6387 | 2018-02-13 | Yes |
| 857-344 | QUINCY | 6387 | 2018-04-09 | Yes |
| 857-345 | HYDE PARK | 6387 | — | Yes |
| 857-346 | BOSTON | 148J | 2018-05-23 | Yes |
| 857-347 | BOSTON | 181J | 2018-07-13 | Yes |
| 857-348 | BOSTON | 4036 | — | Yes |
| 857-349 | WINTHROP | 990E | 2018-09-20 | Yes |
| 857-350 | BOSTON | 6387 | 2007-06-18 | Yes |
| 857-351 | ROXBURY | 6889 | 2024-05-17 | Yes |
| 857-352 | BROOKLINE | 6889 | 2015-01-22 | Yes |
| 857-353 | BOSTON | 7229 | 2020-01-06 | Yes |
| 857-354 | BOSTON | 6889 | 2018-11-21 | Yes |
| 857-355 | EVERETT | 428H | 2019-10-07 | Yes |
| 857-356 | BOSTON | 6889 | 2019-10-11 | Yes |
| 857-357 | CAMBRIDGE | 007J | 2019-12-24 | Yes |
| 857-358 | QUINCY | 4036 | 2020-03-23 | Yes |
| 857-359 | QUINCY | 6387 | 2020-03-24 | Yes |
| 857-360 | BOSTON | 6387 | 2015-10-07 | Yes |
| 857-361 | BROOKLINE | 6889 | — | Yes |
| 857-362 | BOSTON | 9102 | 2006-07-19 | Yes |
| 857-363 | EVERETT | 6387 | 2001-04-24 | Yes |
| 857-364 | BROOKLINE | 829J | 2001-03-20 | Yes |
| 857-365 | BOSTON | 478J | 2020-05-29 | Yes |
| 857-366 | BOSTON | 6387 | 2006-03-15 | Yes |
| 857-367 | WATERTOWN | 7135 | 2020-10-05 | Yes |
| 857-368 | BOSTON | 829J | 2011-08-02 | Yes |
| 857-369 | BOSTON | 268F | 2020-12-21 | Yes |
| 857-370 | BROOKLINE | 6889 | 2021-03-26 | Yes |
| 857-371 | WATERTOWN | 892D | — | Yes |
| 857-372 | QUINCY | 6387 | 2021-05-17 | Yes |
| 857-373 | BELMONT | 829J | 2001-03-20 | Yes |
| 857-374 | QUINCY | 892D | 2021-06-14 | Yes |
| 857-375 | DORCHESTER | 892D | 2021-06-14 | Yes |
| 857-376 | BROOKLINE | 6889 | 2021-06-29 | Yes |
| 857-377 | BOSTON | 829J | 2014-04-09 | Yes |
| 857-378 | BOSTON | 9102 | 2017-02-01 | Yes |
| 857-379 | ROXBURY | 939H | 2021-07-28 | Yes |
| 857-380 | EASTBOSTON | 892D | 2020-05-13 | Yes |
| 857-381 | BROOKLINE | 6889 | 2021-09-09 | Yes |
| 857-382 | EASTBOSTON | 892D | 2021-06-14 | Yes |
| 857-383 | BOSTON | 7135 | 2005-11-01 | Yes |
| 857-384 | BRIGHTON | 892D | 2021-07-16 | Yes |
| 857-385 | DORCHESTER | 4036 | 2016-06-01 | Yes |
| 857-386 | CHELSEA | 9102 | 2016-08-04 | Yes |
| 857-387 | QUINCY | 318J | 2021-09-10 | Yes |
| 857-388 | SOMERVILLE | 939H | 2021-09-24 | Yes |
| 857-389 | CHARLESTN | 6889 | 2001-12-14 | Yes |
| 857-390 | BROOKLINE | 6889 | 2021-10-07 | Yes |
| 857-391 | CHARLESTN | 6889 | 2021-12-03 | Yes |
| 857-392 | JAMAICA PL | 892D | 2021-06-14 | Yes |
| 857-393 | BOSTON | 6387 | 2017-01-23 | Yes |
| 857-394 | BELMONT | 7229 | 2021-12-08 | Yes |
| 857-395 | ROXBURY | 6889 | 2022-01-27 | Yes |
| 857-396 | BROOKLINE | 6889 | 2022-07-28 | Yes |
| 857-397 | ROXBURY | 6889 | 2022-07-28 | Yes |
| 857-398 | ROXBURY | 6889 | 2022-09-21 | Yes |
| 857-399 | ROXBURY | 990E | 2001-06-29 | Yes |
These are initial assignees from NANPA CO-code records — because of number portability, the current serving carrier of individual numbers may differ. Bulk export requires a membership.