All assignees
596 prefixes in 231 · initial assignments from the NANPA CO code file, 09/17/2026
| NPA-NXX | Rate center | OCN | Assigned | Pooled |
|---|---|---|---|---|
| 231-200 | — | — | ||
| 231-201 | CHIPPEWALK | 6534 | 2004-03-05 | Yes |
| 231-202 | MECOSTA | 6534 | 2004-03-05 | Yes |
| 231-203 | ALANSON | 6534 | 2004-03-19 | Yes |
| 231-204 | FIFE LAKE | 6630 | — | — |
| 231-205 | BRUTUS | 817J | 2004-03-24 | — |
| 231-206 | MUSKEGON | 2964 | — | Yes |
| 231-207 | HONOR | 817J | 2004-03-24 | — |
| 231-208 | BOYNEFALLS | 817J | 2004-03-24 | — |
| 231-209 | SUTTONSBAY | 817J | 2004-03-25 | — |
| 231-210 | ST JAMES | 543C | 2023-07-11 | Yes |
| 231-211 | XXXXXXXXXX | MULT | — | — |
| 231-212 | INTERLOCHN | 508J | 2016-07-25 | Yes |
| 231-213 | TRAVERSECY | 9323 | 2015-03-26 | Yes |
| 231-214 | LAKE NORTH | 792K | 2025-03-12 | Yes |
| 231-215 | MUSKEGON | 6003 | — | — |
| 231-216 | FRANKFORT | 933G | 2015-12-01 | Yes |
| 231-217 | BEAR LAKE | 817J | 2004-03-24 | — |
| 231-218 | TRAVERSECY | 2964 | — | Yes |
| 231-219 | MERRITT | 817J | 2004-03-24 | — |
| 231-220 | MUSKEGON | 2550 | 2003-03-25 | Yes |
| 231-221 | HARBOR SPG | 508J | 2015-06-01 | Yes |
| 231-222 | EASTJORDAN | 6120 | 2002-04-04 | Yes |
| 231-223 | OLDMISSION | 0720 | — | Yes |
| 231-224 | FREMONT | 991E | — | Yes |
| 231-225 | FREMONT | 6120 | 2002-04-04 | Yes |
| 231-226 | GLEN LAKE | 817J | 2004-03-24 | — |
| 231-227 | HONOR | 792K | 2012-09-26 | Yes |
| 231-228 | GLEN LAKE | 0702 | — | — |
| 231-229 | MOORESTOWN | 0702 | — | — |
| 231-230 | ELMIRA | 817J | 2004-03-24 | — |
| 231-231 | — | — | ||
| 231-232 | MOORESTOWN | 817J | 2004-03-24 | — |
| 231-233 | LUDINGTON | 6003 | 2004-08-30 | — |
| 231-234 | BUCKLEY | 792K | 2015-12-07 | Yes |
| 231-235 | LEVERING | 817J | 2004-03-24 | — |
| 231-236 | LAKE CITY | 817J | 2004-03-24 | — |
| 231-237 | CHARLEVOIX | 9323 | — | Yes |
| 231-238 | INDIAN RIV | 9323 | — | Yes |
| 231-239 | LUDINGTON | 6003 | 2004-04-28 | Yes |
| 231-240 | LAKE ANN | 817J | 2004-03-24 | — |
| 231-241 | PENTWATER | 993L | 2006-10-10 | Yes |
| 231-242 | HARBOR SPG | 9323 | — | Yes |
| 231-243 | ALANSON | 817J | 2004-03-24 | — |
| 231-244 | BOYNE CITY | 508J | 2015-08-26 | Yes |
| 231-245 | NEWAYGO | 6534 | 2009-07-17 | Yes |
| 231-246 | MUSKEGON | 318J | 2015-12-22 | Yes |
| 231-247 | WILLIAMSBG | 991E | 2018-09-28 | Yes |
| 231-248 | — | — | ||
| 231-249 | CHEBOYGAN | 991E | — | — |
| 231-250 | BIG RAPIDS | 6003 | — | — |
| 231-251 | LKLEELANAU | 933G | 2015-12-02 | Yes |
| 231-252 | TRAVERSECY | 991E | 2016-04-18 | Yes |
| 231-253 | CADILLAC | 2964 | 2018-11-08 | Yes |
| 231-254 | PETOSKEY | 2964 | 2019-10-24 | Yes |
| 231-255 | ONEKAMA | 6630 | — | — |
| 231-256 | LKLEELANAU | 9323 | — | Yes |
| 231-257 | LAKE CITY | 116F | 2019-02-27 | Yes |
| 231-258 | KALKASKA | 9323 | — | — |
| 231-259 | SHELBY | 792K | 2007-02-07 | Yes |
| 231-260 | MUSKEGON | 2964 | 2017-03-03 | Yes |
| 231-261 | LUDINGTON | 116F | 2018-12-31 | Yes |
| 231-262 | ELMIRA | 3535 | 2005-01-21 | Yes |
| 231-263 | KINGSLEY | 0705 | — | Yes |
| 231-264 | ELK RAPIDS | 9323 | — | Yes |
| 231-265 | CORAL | 792K | 2014-05-19 | Yes |
| 231-266 | IRONS | 9323 | — | Yes |
| 231-267 | WILLIAMSBG | 9323 | — | Yes |
| 231-268 | CHEBOYGAN | 6003 | 2004-07-12 | Yes |
| 231-269 | BUCKLEY | 0704 | — | — |
| 231-270 | BOYNE CITY | 543C | 2021-05-21 | Yes |
| 231-271 | SUTTONSBAY | 0702 | — | — |
| 231-272 | KINGSLEY | 543C | 2019-08-08 | Yes |
| 231-273 | EASTPORT | 543C | 2020-10-26 | Yes |
| 231-274 | TRAVERSECY | 9748 | — | — |
| 231-275 | LAKE ANN | 0702 | — | — |
| 231-276 | INTERLOCHN | 9323 | — | Yes |
| 231-277 | FOUNTAIN | 543C | 2016-03-22 | Yes |
| 231-278 | HESPERIA | 624H | 2020-10-26 | Yes |
| 231-279 | BIG RAPIDS | 6120 | 2019-12-20 | Yes |
| 231-280 | MANCELONA | 543C | 2016-02-29 | Yes |
| 231-281 | CADILLAC | 6534 | 2020-11-03 | Yes |
| 231-282 | GRANT | 6534 | — | Yes |
| 231-283 | MUSKEGON | 543C | 2020-11-09 | Yes |
| 231-284 | MANISTEE | 2964 | 2021-03-01 | Yes |
| 231-285 | CADILLAC | 2964 | 2020-01-09 | Yes |
| 231-286 | MUSKEGON | 6003 | — | — |
| 231-287 | BIG RAPIDS | 6003 | — | Yes |
| 231-288 | MUSKEGON | 6534 | 2005-09-13 | Yes |
| 231-289 | CHARLEVOIX | 991E | 2018-07-19 | Yes |
| 231-290 | INDIAN RIV | 6534 | — | Yes |
| 231-291 | MUSKEGON | 817J | 2012-05-11 | Yes |
| 231-292 | WHITEHALL | 792K | 2010-07-30 | Yes |
| 231-293 | FRANKFORT | 321J | 2021-05-14 | Yes |
| 231-294 | FIFE LAKE | 543C | 2021-06-15 | Yes |
| 231-295 | LAKE CITY | 792K | 2012-09-26 | Yes |
| 231-296 | FREMONT | 792K | 2021-05-13 | Yes |
| 231-297 | KINGSLEY | 543C | 2021-06-25 | Yes |
| 231-298 | IRONS | 792K | 2021-05-13 | Yes |
| 231-299 | MANISTEE | 5562 | 2011-12-28 | 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.