All assignees
596 prefixes in 231 · initial assignments from the NANPA CO code file, 09/17/2026
| NPA-NXX | Rate center | OCN | Assigned | Pooled |
|---|---|---|---|---|
| 231-300 | ALDEN | 543C | 2017-09-07 | Yes |
| 231-301 | HART | 6003 | — | Yes |
| 231-302 | PETOSKEY | 991E | — | — |
| 231-303 | NEWAYGO | 770E | 2011-05-16 | Yes |
| 231-304 | BRUTUS | 543C | 2020-10-26 | Yes |
| 231-305 | BIG RAPIDS | 817J | — | — |
| 231-306 | CADILLAC | 817J | — | — |
| 231-307 | MORLEY | 6534 | — | Yes |
| 231-308 | CHARLEVOIX | 817J | — | — |
| 231-309 | MANISTEE | 817J | — | — |
| 231-310 | FALMOUTH | 543C | 2018-09-25 | Yes |
| 231-311 | XXXXXXXXXX | MULT | — | — |
| 231-312 | FRANKFORT | 817J | — | — |
| 231-313 | TRAVERSECY | 6534 | — | — |
| 231-314 | KALKASKA | 817J | — | — |
| 231-315 | MUSKEGON | 6630 | — | — |
| 231-316 | LUDINGTON | 817J | — | — |
| 231-317 | BOYNE CITY | 6630 | — | — |
| 231-318 | TRAVERSECY | 6630 | — | — |
| 231-319 | MACKINAWCY | 817J | — | — |
| 231-320 | TRCHRIVBDG | 991E | 2021-09-03 | Yes |
| 231-321 | ELMIRA | 6003 | 2021-05-19 | Yes |
| 231-322 | TRCHRIVBDG | 0695 | — | Yes |
| 231-323 | EASTJORDAN | 991E | — | — |
| 231-324 | HARBOR SPG | 770E | 2021-05-25 | Yes |
| 231-325 | HONOR | 0702 | — | — |
| 231-326 | GLEN LAKE | 0702 | — | — |
| 231-327 | MUSKEGON | 6534 | — | Yes |
| 231-328 | MERRITT | 0702 | — | Yes |
| 231-329 | MUSKEGON | 6534 | — | — |
| 231-330 | PETOSKEY | 6003 | 2002-12-10 | — |
| 231-331 | ALDEN | 0695 | — | Yes |
| 231-332 | MUSKEGON | 817J | — | — |
| 231-333 | CHEBOYGAN | 6120 | 2002-04-04 | Yes |
| 231-334 | GLEN LAKE | 0702 | — | — |
| 231-335 | FREMONT | 6534 | — | Yes |
| 231-336 | LUDINGTON | 6630 | — | — |
| 231-337 | MCBAIN | 6534 | — | — |
| 231-338 | BALDWIN | 991E | — | Yes |
| 231-339 | MUSKEGON | 9748 | — | — |
| 231-340 | ELMIRA | 6003 | 2003-07-09 | Yes |
| 231-341 | LAKE ANN | 6534 | 2025-05-22 | Yes |
| 231-342 | TRAVERSECY | 6003 | — | — |
| 231-343 | MUSKEGON | 2964 | — | Yes |
| 231-344 | PETOSKEY | 817J | — | — |
| 231-345 | REED CITY | 991E | — | Yes |
| 231-346 | TRAVERSECY | 817J | — | — |
| 231-347 | PETOSKEY | 9323 | — | — |
| 231-348 | PETOSKEY | 9323 | — | — |
| 231-349 | BIG RAPIDS | 6003 | — | — |
| 231-350 | BELLAIRE | 6003 | 2003-07-09 | Yes |
| 231-351 | SCOTTVILLE | 817J | — | — |
| 231-352 | FRANKFORT | 9323 | — | Yes |
| 231-353 | MCBAIN | 817J | — | — |
| 231-354 | CORAL | 9323 | — | Yes |
| 231-355 | FREMONT | 817J | — | — |
| 231-356 | MANCELONA | 817J | — | — |
| 231-357 | TRAVERSECY | 6003 | — | — |
| 231-358 | CENTRAL LK | 817J | — | — |
| 231-359 | MECOSTA | 792K | 2012-09-26 | Yes |
| 231-360 | TRAVERSECY | 6534 | 2002-12-30 | Yes |
| 231-361 | MORLEY | 817J | — | — |
| 231-362 | KALEVA | 0703 | — | — |
| 231-363 | CHEBOYGAN | 817J | — | — |
| 231-364 | NORTHPORT | 543C | 2021-06-15 | Yes |
| 231-365 | WOLVERINE | 817J | — | — |
| 231-366 | FRUITPORT | 6120 | 2003-02-27 | Yes |
| 231-367 | WOLVERINE | 543C | 2021-06-25 | Yes |
| 231-368 | BALDWIN | 817J | — | — |
| 231-369 | SOBOARDMAN | 0704 | — | — |
| 231-370 | MUSKEGON | 2964 | 2021-09-03 | Yes |
| 231-371 | TUSTIN | 991E | 2021-09-03 | Yes |
| 231-372 | EVART | 817J | — | — |
| 231-373 | PETOSKEY | 6003 | 2004-04-27 | Yes |
| 231-374 | SHELBY | 543C | 2021-06-15 | Yes |
| 231-375 | MUSKEGON | 6003 | — | Yes |
| 231-376 | TWIN LAKE | 543C | 2021-07-02 | Yes |
| 231-377 | CLAM RIVER | 0695 | — | Yes |
| 231-378 | COPESHTNVL | 0704 | — | — |
| 231-379 | ONEKAMA | 991E | 2021-08-26 | Yes |
| 231-380 | NEWAYGO | 2964 | 2022-01-10 | Yes |
| 231-381 | WHITECLOUD | 792K | 2021-05-13 | Yes |
| 231-383 | BEULAH | 6003 | 2003-04-29 | Yes |
| 231-384 | KALKASKA | 6003 | 2003-05-01 | Yes |
| 231-385 | CORAL | 543C | 2021-07-20 | Yes |
| 231-386 | NORTHPORT | 9323 | — | Yes |
| 231-387 | PETOSKEY | 6534 | 2021-10-06 | Yes |
| 231-388 | LE ROY | 6003 | 2003-05-01 | Yes |
| 231-389 | HARRIETTA | 9323 | — | Yes |
| 231-390 | BIG RAPIDS | 2964 | 2021-10-26 | Yes |
| 231-391 | WALLOON LK | 991E | 2022-03-10 | Yes |
| 231-392 | TRAVERSECY | 2964 | 2001-01-09 | Yes |
| 231-393 | LE ROY | 624H | 2021-07-02 | Yes |
| 231-394 | MOORESTOWN | 6003 | 2003-07-29 | Yes |
| 231-395 | GRANT | 817J | — | — |
| 231-396 | CADILLAC | 543C | 2021-10-29 | Yes |
| 231-397 | MANISTEE | 2964 | 2021-11-03 | Yes |
| 231-398 | MANISTEE | 9323 | — | Yes |
| 231-399 | FRANKFORT | 3535 | 2005-01-19 | Yes |
| 231-400 | ALANSON | 543C | 2019-10-10 | 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.