All assignees
798 prefixes in 312 · initial assignments from the NANPA CO code file, 09/17/2026
| NPA-NXX | Rate center | OCN | Assigned | Pooled |
|---|---|---|---|---|
| 312-400 | CHICGOZN01 | 9748 | 2001-04-13 | — |
| 312-401 | CHICGOZN01 | 6534 | — | — |
| 312-402 | CHICGOZN01 | 6534 | — | Yes |
| 312-403 | LA GRANGE | 6333 | — | Yes |
| 312-404 | CHICGOZN01 | 6529 | 2002-10-14 | — |
| 312-405 | CHICGOZN01 | 6333 | — | — |
| 312-406 | WHEELING | 6534 | — | Yes |
| 312-407 | CHICGOZN01 | 9329 | — | — |
| 312-408 | CHICGOZN01 | 9329 | — | — |
| 312-409 | CHICGOZN01 | 9329 | — | Yes |
| 312-410 | CHICGOZN01 | 9329 | — | — |
| 312-411 | XXXXXXXXXX | MULT | — | — |
| 312-412 | WHEELING | 6534 | — | Yes |
| 312-413 | CHICGOZN01 | 9329 | — | — |
| 312-414 | CHICGOZN01 | 197D | 2016-08-12 | Yes |
| 312-415 | CHICGOZN01 | 6333 | — | — |
| 312-416 | CHICGOZN01 | 7196 | — | — |
| 312-417 | CHICGOZN01 | 9329 | — | — |
| 312-418 | CHICGOZN01 | 6630 | — | — |
| 312-419 | CHICGOZN01 | 9329 | — | — |
| 312-420 | CHICGOZN01 | 6534 | — | — |
| 312-421 | CHICGOZN01 | 9329 | — | — |
| 312-422 | CHICGOZN01 | 9329 | — | — |
| 312-423 | CHICGOZN01 | 6115 | — | Yes |
| 312-424 | CHICGOZN01 | 9329 | — | — |
| 312-425 | CHICGOZN01 | 9329 | — | — |
| 312-426 | CHICGOZN01 | 224C | 2026-01-27 | Yes |
| 312-427 | CHICGOZN01 | 9329 | — | — |
| 312-428 | CHICGOZN01 | 6115 | — | Yes |
| 312-429 | CHICGOZN01 | 6115 | — | Yes |
| 312-430 | CHICGOZN01 | 9329 | — | — |
| 312-431 | CHICGOZN01 | 9329 | — | — |
| 312-432 | CHICGOZN01 | 9329 | — | — |
| 312-433 | CHICGOZN01 | 9329 | — | Yes |
| 312-434 | CHICGOZN01 | 6529 | 2011-07-08 | Yes |
| 312-435 | CHICGOZN01 | 9329 | — | — |
| 312-436 | CHICGOZN01 | 9329 | — | Yes |
| 312-437 | CHICGOZN01 | 6529 | — | Yes |
| 312-438 | CHICGOZN01 | 6333 | 2017-06-02 | Yes |
| 312-439 | CHICGOZN01 | 6534 | 2016-11-28 | Yes |
| 312-440 | CHICGOZN01 | 9329 | — | — |
| 312-441 | CHICGOZN01 | 9329 | — | — |
| 312-442 | CHICGOZN01 | 9329 | — | Yes |
| 312-443 | CHICGOZN01 | 9329 | — | Yes |
| 312-444 | CHICGOZN01 | 9329 | — | Yes |
| 312-445 | CHICGOZN01 | 9329 | — | Yes |
| 312-446 | CHICGOZN01 | 6529 | — | Yes |
| 312-447 | CHICGOZN01 | 9329 | — | Yes |
| 312-448 | CHICGOZN01 | 6333 | 2011-08-02 | Yes |
| 312-449 | CHICGOZN01 | 700J | 2025-07-21 | Yes |
| 312-450 | CHICGOZN01 | 6534 | — | Yes |
| 312-451 | CHICGOZN01 | 6529 | — | Yes |
| 312-452 | CHICGOZN01 | 624H | 2025-09-02 | Yes |
| 312-453 | CHICGOZN01 | 7196 | — | — |
| 312-454 | CHICGOZN01 | 9329 | — | — |
| 312-455 | CHICGOZN01 | 9329 | — | — |
| 312-456 | CHICGOZN01 | 9329 | — | — |
| 312-457 | CHICGOZN01 | 9748 | 2001-04-23 | — |
| 312-458 | CHICGOZN01 | 9329 | — | Yes |
| 312-459 | CHICGOZN01 | 6529 | 2011-08-02 | Yes |
| 312-460 | CHICGOZN01 | 9329 | — | Yes |
| 312-461 | CHICGOZN01 | 9329 | — | — |
| 312-462 | CHICGOZN01 | 9329 | — | Yes |
| 312-463 | CHICGOZN01 | 9329 | — | Yes |
| 312-464 | CHICGOZN01 | 9329 | — | — |
| 312-465 | CHICGOZN01 | 829J | 2009-03-26 | Yes |
| 312-466 | CHICGOZN01 | 9329 | — | — |
| 312-467 | CHICGOZN01 | 9329 | — | — |
| 312-468 | CHICGOZN01 | 6529 | 2015-06-26 | Yes |
| 312-469 | CHICGOZN01 | 9329 | — | Yes |
| 312-470 | CHICGOZN01 | 7229 | — | Yes |
| 312-471 | CHICGOZN01 | 7229 | 2015-06-26 | Yes |
| 312-472 | CHICGOZN01 | 9329 | 2005-10-27 | Yes |
| 312-473 | CHICGOZN01 | 224C | 2006-11-15 | Yes |
| 312-474 | CHICGOZN01 | 9329 | — | — |
| 312-475 | CHICGOZN01 | 9329 | — | — |
| 312-476 | CHICGOZN01 | 6529 | — | Yes |
| 312-477 | CHICGOZN01 | 6115 | 2010-10-20 | Yes |
| 312-478 | CHICGOZN01 | 6529 | 2014-03-20 | Yes |
| 312-479 | CHICGOZN01 | 7136 | — | Yes |
| 312-480 | CHICGOZN01 | 6534 | — | Yes |
| 312-481 | CHICGOZN01 | 5562 | 2017-07-07 | Yes |
| 312-482 | CHICGOZN01 | 9329 | — | — |
| 312-483 | CHICGOZN01 | 6529 | 2014-08-22 | Yes |
| 312-484 | CHICGOZN01 | 6630 | — | — |
| 312-485 | CHICGOZN01 | 6333 | — | — |
| 312-486 | CHICGOZN01 | 7229 | 2004-04-23 | Yes |
| 312-487 | CHICGOZN01 | 5562 | 2014-10-27 | Yes |
| 312-488 | CHICGOZN01 | 6115 | — | Yes |
| 312-489 | CHICGOZN01 | 6333 | — | Yes |
| 312-490 | CHICGOZN01 | 6630 | — | — |
| 312-491 | CHICGOZN01 | 9329 | — | — |
| 312-492 | CHICGOZN01 | 9329 | — | Yes |
| 312-493 | CHICGOZN01 | 6529 | — | — |
| 312-494 | CHICGOZN01 | 9329 | — | — |
| 312-495 | CHICGOZN01 | 6630 | — | — |
| 312-496 | CHICGOZN01 | 9329 | — | Yes |
| 312-497 | CHICGOZN01 | 6333 | — | — |
| 312-498 | CHICGOZN01 | 6529 | — | Yes |
| 312-499 | CHICGOZN01 | 9329 | — | — |
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.