All assignees
382 prefixes in 857 · initial assignments from the NANPA CO code file, 09/17/2026
| NPA-NXX | Rate center | OCN | Assigned | Pooled |
|---|---|---|---|---|
| 857-400 | BOSTON | 990E | 2010-11-03 | Yes |
| 857-401 | SO BOSTON | 829J | 2001-03-20 | Yes |
| 857-402 | EASTBOSTON | 321J | — | Yes |
| 857-403 | QUINCY | 829J | 2001-03-20 | Yes |
| 857-404 | NEWTON | 318J | 2007-06-15 | Yes |
| 857-405 | BROOKLINE | 6889 | 2022-11-08 | Yes |
| 857-406 | BOSTON | 6387 | 2015-11-16 | Yes |
| 857-407 | ROXBURY | 4036 | 2015-06-01 | Yes |
| 857-408 | BOSTON | 6387 | 2015-11-25 | Yes |
| 857-409 | BOSTON | 6387 | 2016-09-21 | Yes |
| 857-410 | CHARLESTN | 990E | 2016-08-12 | Yes |
| 857-411 | XXXXXXXXXX | MULT | — | — |
| 857-412 | CAMBRIDGE | 892D | — | Yes |
| 857-413 | BOSTON | 4018 | 2005-09-19 | Yes |
| 857-414 | BRIGHTON | 321J | — | Yes |
| 857-415 | BOSTON | 197D | 2013-07-03 | Yes |
| 857-416 | BOSTON | 671J | 2022-11-17 | Yes |
| 857-417 | BOSTON | 5562 | 2008-08-04 | Yes |
| 857-418 | DORCHESTER | 671J | 2022-11-17 | Yes |
| 857-419 | MILTON | 4036 | 2016-08-08 | Yes |
| 857-420 | CAMBRIDGE | 892D | 2022-11-23 | Yes |
| 857-421 | BROOKLINE | 6889 | 2024-07-01 | Yes |
| 857-422 | SO BOSTON | 892D | 2021-06-14 | Yes |
| 857-423 | BROOKLINE | 6889 | 2019-09-12 | Yes |
| 857-424 | ROXBURY | 4036 | 2016-10-25 | Yes |
| 857-425 | BRIGHTON | 4036 | 2016-09-06 | Yes |
| 857-426 | BROOKLINE | 6889 | 2024-11-01 | Yes |
| 857-427 | BOSTON | 6889 | 2024-11-01 | Yes |
| 857-428 | EVERETT | 892D | 2023-06-09 | Yes |
| 857-429 | ROXBURY | 6889 | 2024-11-01 | Yes |
| 857-430 | BOSTON | 4036 | 2024-11-13 | Yes |
| 857-431 | BOSTON | 700J | 2025-07-10 | Yes |
| 857-432 | BROOKLINE | 6889 | — | Yes |
| 857-433 | BOSTON | 0051 | 2026-05-04 | — |
| 857-434 | CAMBRIDGE | 0051 | 2026-05-04 | — |
| 857-437 | ROXBURY | 6889 | 2019-09-12 | Yes |
| 857-443 | BOSTON | 939H | 2017-05-22 | Yes |
| 857-444 | BOSTON | 268F | 2010-11-22 | Yes |
| 857-445 | BOSTON | 4036 | 2006-03-21 | Yes |
| 857-449 | BOSTON | 318J | 2002-04-02 | — |
| 857-452 | CHARLESTN | 6889 | — | Yes |
| 857-453 | BOSTON | 4018 | 2005-05-19 | Yes |
| 857-465 | BOSTON | 965H | 2020-05-08 | Yes |
| 857-466 | HYDE PARK | 516J | 2022-02-07 | Yes |
| 857-467 | SOMERVILLE | 516J | 2022-02-24 | Yes |
| 857-468 | CHARLESTN | 516J | 2022-02-11 | Yes |
| 857-472 | BOSTON | 4036 | 2001-12-17 | Yes |
| 857-475 | CHELSEA | 892D | 2021-04-01 | Yes |
| 857-477 | JAMAICA PL | 892D | 2016-02-10 | Yes |
| 857-488 | BOSTON | 6387 | 2005-09-13 | Yes |
| 857-491 | BOSTON | 814J | 2021-09-23 | Yes |
| 857-492 | ROXBURY | 6889 | 2002-07-30 | Yes |
| 857-496 | SO BOSTON | 318J | 2004-11-17 | Yes |
| 857-497 | CHARLESTN | 6889 | 2023-08-17 | Yes |
| 857-498 | BRIGHTON | 4036 | 2001-08-24 | Yes |
| 857-499 | QUINCY | 4036 | 2001-03-29 | Yes |
| 857-500 | CAMBRIDGE | 6387 | 2011-04-17 | Yes |
| 857-504 | BOSTON | 4018 | — | Yes |
| 857-505 | BOSTON | 5562 | 2016-09-21 | Yes |
| 857-506 | ROXBURY | 6889 | 2023-10-06 | Yes |
| 857-507 | BOSTON | 6387 | 2016-09-21 | Yes |
| 857-511 | XXXXXXXXXX | MULT | — | — |
| 857-520 | HYDE PARK | 892D | — | Yes |
| 857-523 | SOMERVILLE | 6387 | 2001-05-03 | Yes |
| 857-524 | SO BOSTON | 7229 | 2001-03-27 | Yes |
| 857-526 | QUINCY | 5562 | 2002-07-30 | Yes |
| 857-529 | CAMBRIDGE | 6387 | 2015-02-03 | Yes |
| 857-540 | BRIGHTON | 6889 | — | Yes |
| 857-544 | ROXBURY | 6889 | 2001-11-28 | Yes |
| 857-547 | JAMAICA PL | 829J | 2001-03-20 | Yes |
| 857-550 | BELMONT | 939H | 2023-09-26 | Yes |
| 857-554 | XXXXXXXXXX | 9102 | — | — |
| 857-555 | DIR ASST | MULT | — | — |
| 857-557 | BOSTON | 321J | 2019-08-27 | Yes |
| 857-559 | BRIGHTON | 7229 | 2001-03-27 | Yes |
| 857-565 | BROOKLINE | 6889 | 2023-11-09 | Yes |
| 857-567 | DORCHESTER | 892D | 2020-05-15 | Yes |
| 857-574 | EASTBOSTON | 829J | 2001-03-20 | Yes |
| 857-575 | SOMERVILLE | 892D | 2021-04-01 | Yes |
| 857-576 | BROOKLINE | 990E | — | Yes |
| 857-577 | CHARLESTN | 892D | 2016-02-11 | Yes |
| 857-578 | NEWTON | 506J | 2020-10-09 | Yes |
| 857-579 | BOSTON | 6889 | 2025-01-07 | Yes |
| 857-587 | DORCHESTER | 321J | — | Yes |
| 857-588 | CHARLESTN | 7229 | 2001-03-27 | Yes |
| 857-597 | WINTHROP | 892D | 2021-04-01 | Yes |
| 857-598 | MILTON | 7229 | 2001-03-20 | Yes |
| 857-600 | CAMBRIDGE | 990E | 2011-04-06 | Yes |
| 857-605 | BRIGHTON | 6889 | 2023-10-11 | Yes |
| 857-611 | XXXXXXXXXX | MULT | — | — |
| 857-615 | BOSTON | 5562 | 2009-06-11 | Yes |
| 857-617 | — | — | ||
| 857-626 | BELMONT | 7229 | 2001-06-29 | Yes |
| 857-636 | NEWTON | 6387 | 2001-07-06 | Yes |
| 857-639 | CAMBRIDGE | 516J | 2022-02-15 | Yes |
| 857-654 | BOSTON | 6889 | 2006-10-17 | Yes |
| 857-656 | BOSTON | 6889 | 2024-11-21 | Yes |
| 857-663 | DORCHESTER | 892D | — | Yes |
| 857-666 | BROOKLINE | 892D | 2015-03-23 | Yes |
| 857-675 | ROXBURY | 892D | 2021-04-02 | 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.