All assignees
798 prefixes in 312 · initial assignments from the NANPA CO code file, 09/17/2026
| NPA-NXX | Rate center | OCN | Assigned | Pooled |
|---|---|---|---|---|
| 312-300 | CHICGOZN01 | 6115 | — | Yes |
| 312-301 | HINSDALE | 6534 | — | — |
| 312-302 | CHICGOZN01 | 9329 | — | — |
| 312-303 | WHEELING | 6534 | — | Yes |
| 312-304 | HINSDALE | 6534 | — | Yes |
| 312-305 | NORTHBROOK | 6333 | — | Yes |
| 312-306 | CHICGOZN01 | 9329 | — | — |
| 312-307 | CHICGOZN01 | 6534 | — | — |
| 312-308 | CHICGOZN01 | 9329 | — | — |
| 312-309 | CHICGOZN01 | 9329 | — | — |
| 312-310 | NORTHBROOK | 6333 | — | Yes |
| 312-311 | XXXXXXXXXX | MULT | — | — |
| 312-312 | CHICGOZN01 | 224C | 2018-01-19 | Yes |
| 312-313 | CHICGOZN01 | 224C | 2014-11-10 | Yes |
| 312-314 | HINSDALE | 6534 | — | Yes |
| 312-315 | CHICGOZN01 | 6534 | — | — |
| 312-316 | CHICGOZN01 | 6534 | — | — |
| 312-317 | WHEELING | 6534 | — | Yes |
| 312-318 | LA GRANGE | 6333 | — | Yes |
| 312-319 | CHICGOZN01 | 7229 | 2017-04-28 | Yes |
| 312-320 | CHICGOZN01 | 6534 | — | — |
| 312-321 | CHICGOZN01 | 9329 | — | — |
| 312-322 | CHICGOZN01 | 9329 | — | — |
| 312-323 | CHICGOZN01 | 9748 | 2001-04-13 | — |
| 312-324 | CHICGOZN01 | 6115 | 2001-05-03 | Yes |
| 312-325 | CHICGOZN01 | 9329 | 2003-06-24 | Yes |
| 312-326 | CHICGOZN01 | 9329 | — | — |
| 312-327 | CHICGOZN01 | 7229 | — | — |
| 312-328 | CHICGOZN01 | 9329 | — | — |
| 312-329 | CHICGOZN01 | 9329 | — | — |
| 312-330 | CHICGOZN01 | 6534 | — | — |
| 312-331 | WHEELING | 6534 | — | Yes |
| 312-332 | CHICGOZN01 | 9329 | — | — |
| 312-333 | CHICGOZN01 | 9748 | 2001-04-13 | — |
| 312-334 | CHICGOZN01 | 460K | — | — |
| 312-335 | CHICGOZN01 | 9329 | — | — |
| 312-336 | CHICGOZN01 | 9329 | — | — |
| 312-337 | CHICGOZN01 | 9329 | — | — |
| 312-338 | CHICGOZN01 | 9329 | — | — |
| 312-339 | CHICGOZN01 | 6333 | — | — |
| 312-340 | CHICGOZN01 | 6529 | — | Yes |
| 312-341 | CHICGOZN01 | 9329 | — | — |
| 312-342 | CHICGOZN01 | 6534 | — | — |
| 312-343 | CHICGOZN01 | 6333 | — | — |
| 312-344 | CHICGOZN01 | 9329 | — | Yes |
| 312-345 | CHICGOZN01 | 9329 | — | — |
| 312-346 | CHICGOZN01 | 9329 | — | — |
| 312-347 | CHICGOZN01 | 9329 | — | — |
| 312-348 | CHICGOZN01 | 224C | 2003-11-14 | Yes |
| 312-349 | CHICGOZN01 | 6630 | — | — |
| 312-350 | CHICGOZN01 | 6333 | — | — |
| 312-351 | CHICGOZN01 | 6534 | — | Yes |
| 312-352 | HINSDALE | 6534 | — | Yes |
| 312-353 | CHICGOZN01 | 9329 | — | — |
| 312-354 | ROSELLE | 6534 | — | Yes |
| 312-355 | CHICGOZN01 | 9329 | — | — |
| 312-356 | CHICGOZN01 | 9329 | — | — |
| 312-357 | CHICGOZN01 | 9329 | — | — |
| 312-358 | CHICGOZN01 | 6529 | 2015-07-21 | Yes |
| 312-359 | CHICGOZN01 | 6630 | — | — |
| 312-360 | CHICGOZN01 | 9329 | — | — |
| 312-361 | CHICGOZN01 | 9329 | — | Yes |
| 312-362 | CHICGOZN01 | 9329 | — | — |
| 312-363 | CHICGOZN01 | 8702 | — | Yes |
| 312-364 | CHICGOZN01 | 9329 | — | — |
| 312-365 | CHICGOZN01 | 6630 | — | — |
| 312-366 | CHICGOZN01 | 6534 | 2016-02-03 | Yes |
| 312-367 | LA GRANGE | 6630 | — | — |
| 312-368 | CHICGOZN01 | 9329 | — | — |
| 312-369 | CHICGOZN01 | 6534 | — | Yes |
| 312-370 | CHICGOZN01 | 6630 | — | — |
| 312-371 | CHICGOZN01 | 6529 | — | Yes |
| 312-372 | CHICGOZN01 | 9329 | — | — |
| 312-373 | CHICGOZN01 | 6115 | — | Yes |
| 312-374 | CHICGOZN01 | 9329 | — | Yes |
| 312-375 | CHICGOZN01 | 6529 | — | — |
| 312-376 | CHICGOZN01 | 224C | — | Yes |
| 312-377 | CHICGOZN01 | 7229 | — | — |
| 312-378 | CHICGOZN01 | 6630 | — | — |
| 312-379 | CHICGOZN01 | 829J | 2001-04-10 | Yes |
| 312-380 | CHICGOZN01 | 9329 | — | Yes |
| 312-381 | CHICGOZN01 | 9329 | — | Yes |
| 312-382 | CHICGOZN01 | 9329 | — | — |
| 312-383 | CHICGOZN01 | 7136 | 2016-02-01 | Yes |
| 312-384 | CHICGOZN01 | 9329 | — | Yes |
| 312-385 | CHICGOZN01 | 9329 | — | Yes |
| 312-386 | CHICGOZN01 | 9329 | — | Yes |
| 312-387 | CHICGOZN01 | 6630 | — | — |
| 312-388 | CHICGOZN01 | 6529 | — | Yes |
| 312-389 | CHICGOZN01 | 6630 | — | — |
| 312-390 | CHICGOZN01 | 9748 | 2001-04-16 | — |
| 312-391 | CHICGOZN01 | 6534 | — | — |
| 312-392 | CHICGOZN01 | 224C | 2017-10-23 | Yes |
| 312-393 | CHICGOZN01 | 9748 | 2001-04-23 | — |
| 312-394 | CHICGOZN01 | 9329 | — | Yes |
| 312-395 | CHICGOZN01 | 7136 | — | Yes |
| 312-396 | CHICGOZN01 | 9329 | — | — |
| 312-397 | CHICGOZN01 | 9329 | — | — |
| 312-398 | CHICGOZN01 | 6630 | — | — |
| 312-399 | CHICGOZN01 | 6529 | — | 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.