All assignees
596 prefixes in 231 · initial assignments from the NANPA CO code file, 09/17/2026
| NPA-NXX | Rate center | OCN | Assigned | Pooled |
|---|---|---|---|---|
| 231-534 | TRAVERSECY | 7421 | 2002-10-30 | Yes |
| 231-535 | WALLOON LK | 9323 | — | Yes |
| 231-536 | EASTJORDAN | 9323 | — | Yes |
| 231-537 | LEVERING | 0702 | — | — |
| 231-538 | FREMONT | 2550 | 2002-08-27 | Yes |
| 231-539 | PELLSTON | 9323 | — | Yes |
| 231-544 | CENTRAL LK | 0695 | — | Yes |
| 231-545 | BOYNEFALLS | 792K | 2016-09-23 | Yes |
| 231-546 | ELMIRA | 0702 | — | — |
| 231-547 | CHARLEVOIX | 9323 | — | — |
| 231-548 | ALANSON | 0702 | — | — |
| 231-549 | BOYNEFALLS | 0702 | — | Yes |
| 231-550 | PETOSKEY | 5562 | 2021-09-22 | Yes |
| 231-552 | CHARLEVOIX | 2964 | 2025-07-31 | Yes |
| 231-555 | DIR ASST | MULT | — | — |
| 231-557 | MUSKEGON | 6003 | — | — |
| 231-559 | MCBAIN | 991E | 2012-08-01 | Yes |
| 231-563 | MUSKEGON | 6534 | — | Yes |
| 231-564 | KALKASKA | 6534 | — | Yes |
| 231-566 | HARRIETTA | 516J | 2022-02-22 | Yes |
| 231-567 | MUSKEGON | 770E | 2020-12-02 | Yes |
| 231-568 | TRAVERSECY | 2550 | — | — |
| 231-569 | PETOSKEY | 9748 | — | — |
| 231-570 | FIFE LAKE | 6534 | 2002-03-29 | Yes |
| 231-571 | MUSKEGON | 0695 | — | Yes |
| 231-577 | CADILLAC | 6120 | 2002-05-14 | Yes |
| 231-578 | MUSKEGON | 2964 | — | Yes |
| 231-580 | BIG RAPIDS | 2964 | 2001-02-05 | Yes |
| 231-581 | ALBA | 792K | 2017-04-20 | Yes |
| 231-582 | BOYNE CITY | 9323 | — | — |
| 231-583 | LUDINGTON | 2550 | 2002-08-27 | Yes |
| 231-584 | ALBA | 0721 | — | — |
| 231-585 | LAKE NORTH | 0721 | — | — |
| 231-586 | — | — | ||
| 231-587 | MANCELONA | 9323 | — | Yes |
| 231-588 | ELLSWORTH | 0695 | — | Yes |
| 231-590 | TRAVERSECY | 6003 | — | — |
| 231-591 | BIG RAPIDS | 9323 | — | — |
| 231-592 | BIG RAPIDS | 9323 | — | — |
| 231-593 | CADILLAC | 6630 | — | — |
| 231-594 | HART | 506J | — | Yes |
| 231-596 | HARBOR SPG | 6630 | — | — |
| 231-597 | CHEBOYGAN | 9323 | — | Yes |
| 231-598 | BIG RAPIDS | 6534 | — | Yes |
| 231-599 | EASTPORT | 0695 | — | Yes |
| 231-600 | TRAVERSECY | 965H | 2019-12-19 | Yes |
| 231-604 | KALKASKA | 6630 | — | — |
| 231-605 | NEWAYGO | 6630 | — | — |
| 231-608 | FRANKFORT | 6630 | — | — |
| 231-611 | XXXXXXXXXX | MULT | — | — |
| 231-613 | SCOTTVILLE | 6534 | — | Yes |
| 231-614 | PENTWATER | 2550 | — | — |
| 231-615 | CHEBOYGAN | 9748 | — | — |
| 231-616 | — | — | ||
| 231-620 | TRAVERSECY | 6534 | — | — |
| 231-622 | PETOSKEY | 6120 | 2002-08-19 | Yes |
| 231-624 | KALKASKA | 2964 | — | Yes |
| 231-625 | CHEBOYGAN | 9323 | — | Yes |
| 231-626 | LEVERING | 792K | 2012-09-26 | Yes |
| 231-627 | CHEBOYGAN | 9323 | — | Yes |
| 231-629 | BIG RAPIDS | 2964 | — | Yes |
| 231-631 | TRAVERSECY | 6003 | 2001-08-31 | — |
| 231-632 | TRAVERSECY | 6534 | — | — |
| 231-633 | TRAVERSECY | 6534 | — | — |
| 231-634 | BOIS BLANC | 0677 | — | Yes |
| 231-635 | MACKINAWCY | 2550 | 2002-08-27 | — |
| 231-636 | HOWARDCITY | 2550 | 2002-08-12 | Yes |
| 231-637 | NORTHPORT | 817J | 2001-08-31 | — |
| 231-638 | MUSKEGON | 2964 | 2001-03-09 | Yes |
| 231-639 | BEULAH | 2550 | 2002-08-27 | — |
| 231-640 | LAKE ANN | 6534 | 2002-08-30 | Yes |
| 231-642 | TRAVERSECY | 2964 | 2001-04-02 | Yes |
| 231-643 | MORLEY | 2550 | 2002-08-27 | Yes |
| 231-645 | TRAVERSECY | 6534 | — | — |
| 231-646 | ELLSWORTH | 0695 | 2001-06-18 | Yes |
| 231-647 | CORAL | 817J | 2001-08-27 | — |
| 231-648 | HOWARDCITY | 6120 | — | Yes |
| 231-649 | TRAVERSECY | 6003 | 2002-07-19 | — |
| 231-651 | BEULAH | 6534 | 2002-08-30 | Yes |
| 231-652 | NEWAYGO | 9323 | — | Yes |
| 231-655 | MANISTEE | 6003 | 2014-12-19 | Yes |
| 231-656 | KALKASKA | 2550 | 2002-08-27 | — |
| 231-660 | BIG RAPIDS | 2550 | 2002-08-27 | Yes |
| 231-663 | MESICK | 516J | 2022-03-07 | Yes |
| 231-666 | MUSKEGON | 543C | 2017-10-09 | Yes |
| 231-667 | MARION | 6534 | 2002-08-30 | Yes |
| 231-668 | TRAVERSECY | 6120 | 2002-04-29 | Yes |
| 231-670 | MUSKEGON | 6003 | 2001-02-21 | Yes |
| 231-672 | MUSKEGON | 770E | 2001-11-12 | Yes |
| 231-674 | GRANT | 6120 | 2001-05-18 | Yes |
| 231-675 | BOYNE CITY | 6534 | 2002-03-29 | — |
| 231-676 | BELLAIRE | 6534 | 2002-08-30 | Yes |
| 231-678 | BRETHREN | 3535 | 2005-01-19 | Yes |
| 231-679 | BIG RAPIDS | 6003 | 2002-10-24 | Yes |
| 231-680 | REED CITY | 6120 | 2002-08-19 | Yes |
| 231-681 | FRUITPORT | 0695 | 2001-06-18 | Yes |
| 231-682 | ALDEN | 817J | 2002-04-22 | — |
| 231-683 | MUSKEGON | 6120 | 2001-07-09 | Yes |
| 231-685 | RAVENNA | 792K | 2014-09-25 | Yes |
| 231-686 | FRANKFORT | 2550 | 2002-08-27 | — |
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.