All assignees
798 prefixes in 312 · initial assignments from the NANPA CO code file, 09/17/2026
| NPA-NXX | Rate center | OCN | Assigned | Pooled |
|---|---|---|---|---|
| 312-200 | CHICGOZN01 | 5562 | 2017-10-02 | Yes |
| 312-201 | CHICGOZN01 | 9329 | — | — |
| 312-202 | CHICGOZN01 | 9329 | — | Yes |
| 312-203 | CHICGOZN01 | 6534 | — | — |
| 312-204 | CHICGOZN01 | 9329 | — | Yes |
| 312-205 | CHICGOZN01 | 7229 | — | — |
| 312-206 | CHICGOZN01 | 6534 | — | — |
| 312-207 | CHICGOZN01 | 9329 | — | Yes |
| 312-208 | CHICGOZN01 | 6534 | — | — |
| 312-209 | NORTHBROOK | 6333 | — | Yes |
| 312-210 | CHICGOZN01 | 063E | — | Yes |
| 312-211 | XXXXXXXXXX | MULT | — | — |
| 312-212 | CHICGOZN01 | 9329 | — | Yes |
| 312-213 | CHICGOZN01 | 6534 | — | — |
| 312-214 | CHICGOZN01 | 9329 | — | — |
| 312-215 | WHEELING | 6534 | — | Yes |
| 312-216 | CHICGOZN01 | 460K | 2012-02-13 | Yes |
| 312-217 | CHICGOZN01 | 6529 | — | Yes |
| 312-218 | CHICGOZN01 | 6534 | — | — |
| 312-219 | CHICGOZN01 | 984E | 2012-04-10 | Yes |
| 312-220 | CHICGOZN01 | 9329 | — | — |
| 312-221 | CHICGOZN01 | 6529 | 2011-06-17 | Yes |
| 312-222 | CHICGOZN01 | 9329 | — | — |
| 312-223 | CHICGOZN01 | 9329 | — | — |
| 312-224 | CHICGOZN01 | 6115 | — | — |
| 312-225 | CHICGOZN01 | 9329 | — | — |
| 312-226 | CHICGOZN01 | 9329 | — | — |
| 312-227 | CHICGOZN01 | 9329 | 2010-09-15 | Yes |
| 312-228 | CHICGOZN01 | 9329 | — | — |
| 312-229 | CHICGOZN01 | 9329 | — | Yes |
| 312-230 | CHICGOZN01 | 9329 | — | Yes |
| 312-231 | ROSELLE | 6534 | — | — |
| 312-232 | CHICGOZN01 | 9748 | 2001-04-23 | — |
| 312-233 | CHICGOZN01 | 9329 | — | Yes |
| 312-234 | CHICGOZN01 | 9329 | — | Yes |
| 312-235 | CHICGOZN01 | 9329 | — | Yes |
| 312-236 | CHICGOZN01 | 9329 | — | — |
| 312-237 | CHICGOZN01 | 6333 | — | Yes |
| 312-238 | CHICGOZN01 | 6115 | — | Yes |
| 312-239 | CHICGOZN01 | 7421 | — | Yes |
| 312-240 | CHICGOZN01 | 9329 | — | — |
| 312-241 | CHICGOZN01 | 6534 | 2011-08-17 | Yes |
| 312-242 | CHICGOZN01 | 7136 | — | Yes |
| 312-243 | CHICGOZN01 | 9329 | — | — |
| 312-244 | CHICGOZN01 | 9329 | — | Yes |
| 312-245 | CHICGOZN01 | 9329 | — | — |
| 312-246 | WHEELING | 6534 | — | Yes |
| 312-247 | CHICGOZN01 | 460K | 2004-04-06 | Yes |
| 312-248 | CHICGOZN01 | 5562 | 2014-07-01 | Yes |
| 312-249 | CHICGOZN01 | 6630 | — | — |
| 312-250 | CHICGOZN01 | 6630 | — | — |
| 312-251 | CHICGOZN01 | 9329 | — | — |
| 312-252 | CHICGOZN01 | 7229 | — | Yes |
| 312-253 | CHICGOZN01 | 7229 | — | Yes |
| 312-254 | CHICGOZN01 | 7229 | — | Yes |
| 312-255 | CHICGOZN01 | 9329 | — | Yes |
| 312-256 | CHICGOZN01 | 7229 | — | Yes |
| 312-257 | CHICGOZN01 | 6333 | 2011-08-18 | Yes |
| 312-258 | CHICGOZN01 | 9329 | — | — |
| 312-259 | CHICGOZN01 | 6534 | — | — |
| 312-260 | CHICGOZN01 | 7229 | — | Yes |
| 312-261 | CHICGOZN01 | 6115 | — | Yes |
| 312-262 | CHICGOZN01 | 7229 | — | Yes |
| 312-263 | CHICGOZN01 | 9329 | — | — |
| 312-264 | CHICGOZN01 | 6115 | — | — |
| 312-265 | CHICGOZN01 | 5447 | 2005-11-29 | Yes |
| 312-266 | CHICGOZN01 | 9329 | — | — |
| 312-267 | CHICGOZN01 | 9329 | — | Yes |
| 312-268 | CHICGOZN01 | 6115 | — | Yes |
| 312-269 | CHICGOZN01 | 9329 | — | — |
| 312-270 | CHICGOZN01 | 5562 | 2017-01-16 | Yes |
| 312-271 | CHICGOZN01 | 6630 | — | — |
| 312-272 | CHICGOZN01 | 6630 | — | — |
| 312-273 | CHICGOZN01 | 6333 | 2011-09-13 | Yes |
| 312-274 | CHICGOZN01 | 9329 | — | — |
| 312-275 | CHICGOZN01 | 7229 | — | — |
| 312-276 | CHICGOZN01 | 7229 | — | — |
| 312-277 | CHICGOZN01 | 7229 | — | — |
| 312-278 | CHICGOZN01 | 6115 | — | Yes |
| 312-279 | CHICGOZN01 | 7229 | — | — |
| 312-280 | CHICGOZN01 | 9329 | — | — |
| 312-281 | CHICGOZN01 | 6115 | — | Yes |
| 312-282 | CHICGOZN01 | 6534 | — | — |
| 312-283 | CHICGOZN01 | 6115 | — | Yes |
| 312-284 | CHICGOZN01 | 7056 | — | Yes |
| 312-285 | CHICGOZN01 | 6529 | — | Yes |
| 312-286 | CHICGOZN01 | 6534 | — | — |
| 312-287 | CHICGOZN07 | 6529 | — | Yes |
| 312-288 | CHICGOZN01 | 7229 | — | Yes |
| 312-289 | CHICGOZN01 | 6630 | — | — |
| 312-290 | CHICGOZN01 | 6630 | — | — |
| 312-291 | CHICGOZN01 | 9329 | — | Yes |
| 312-292 | CHICGOZN01 | 984E | 2011-09-02 | Yes |
| 312-293 | CHICGOZN01 | 9329 | — | — |
| 312-294 | CHICGOZN01 | 9329 | — | — |
| 312-295 | LA GRANGE | 6630 | — | — |
| 312-296 | CHICGOZN01 | 6529 | — | Yes |
| 312-297 | CHICGOZN01 | 9329 | — | — |
| 312-298 | CHICGOZN01 | 8702 | — | Yes |
| 312-299 | CHICGOZN01 | 6630 | — | — |
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.