All assignees
768 prefixes in 406 · initial assignments from the NANPA CO code file, 09/17/2026
| NPA-NXX | Rate center | OCN | Assigned | Pooled |
|---|---|---|---|---|
| 406-702 | BILLINGS | 792K | 2012-03-07 | Yes |
| 406-703 | COLUMBUS | 073H | 2021-05-24 | Yes |
| 406-707 | LEWISTOWN | 145J | — | Yes |
| 406-708 | LEWISTOWN | 743G | 2005-02-16 | Yes |
| 406-709 | LAKESIDE | 792K | — | Yes |
| 406-711 | XXXXXXXXXX | MULT | — | — |
| 406-717 | BILLINGS | 197D | 2018-06-06 | Yes |
| 406-718 | DARBY | 506J | — | Yes |
| 406-719 | FROMBERG | 506J | — | Yes |
| 406-720 | COLSTRIP | 6564 | — | Yes |
| 406-721 | MISSOULA | 9636 | — | — |
| 406-722 | ALBERTON | 2235 | — | Yes |
| 406-723 | BUTTE | 9636 | — | — |
| 406-724 | GLENTANA | 2247 | — | Yes |
| 406-725 | LARSLAN | 2247 | — | — |
| 406-726 | ARLEE | 2235 | — | Yes |
| 406-727 | GREATFALLS | 9636 | — | — |
| 406-728 | MISSOULA | 9636 | — | — |
| 406-729 | WILSALL | 508J | 2016-09-08 | Yes |
| 406-730 | WHITEFISH | 792K | — | Yes |
| 406-731 | GREATFALLS | 700J | — | Yes |
| 406-732 | ST MARY | 9636 | — | Yes |
| 406-733 | HIGHWOOD | 2255 | — | — |
| 406-734 | CARTER | 2255 | — | — |
| 406-735 | GEYSER | 2255 | — | — |
| 406-736 | STOCKETT | 2255 | — | Yes |
| 406-737 | GERALDINE | 3310 | — | — |
| 406-738 | RAYNESFORD | 2255 | — | — |
| 406-739 | LOMA | 2257 | — | — |
| 406-740 | COLSTRIP | 6564 | — | Yes |
| 406-741 | HOTSPRINGS | 2241 | — | — |
| 406-742 | FAIRVIEW | 7830 | — | Yes |
| 406-743 | LAUREL | 6010 | 2006-09-08 | Yes |
| 406-744 | STIGNATIUS | 986F | 2012-11-16 | Yes |
| 406-745 | STIGNATIUS | 2235 | — | Yes |
| 406-746 | NASHUA | 2247 | — | — |
| 406-747 | FAIRVIEW | 9636 | — | Yes |
| 406-748 | COLSTRIP | 9636 | — | Yes |
| 406-749 | COLSTRIP | 6010 | — | Yes |
| 406-750 | GREATFALLS | 6564 | 2005-08-22 | — |
| 406-751 | KALISPELL | 2249 | — | — |
| 406-752 | KALISPELL | 2249 | — | — |
| 406-753 | BRADY | 2255 | — | — |
| 406-754 | CONDON | 2235 | — | — |
| 406-755 | KALISPELL | 2249 | — | — |
| 406-756 | KALISPELL | 2249 | — | — |
| 406-757 | DECKER | 2251 | — | Yes |
| 406-758 | KALISPELL | 2249 | — | — |
| 406-759 | CHESTER | 2257 | — | Yes |
| 406-760 | GREATFALLS | 197D | — | Yes |
| 406-761 | GREATFALLS | 9636 | — | — |
| 406-762 | OPHEIM | 2247 | — | Yes |
| 406-763 | GALATNGTWY | 9636 | — | Yes |
| 406-764 | NO FRANNIE | 2296 | — | Yes |
| 406-765 | PLENTYWOOD | 2247 | — | Yes |
| 406-766 | FROID | 2247 | — | — |
| 406-767 | RIDGE | 3410 | — | — |
| 406-768 | POPLAR | 2247 | — | Yes |
| 406-769 | BAINVILLE | 2247 | — | Yes |
| 406-770 | GREATFALLS | 318J | — | Yes |
| 406-771 | GREATFALLS | 9636 | — | — |
| 406-772 | PLEVNA | 2246 | — | Yes |
| 406-773 | RICHEY | 2246 | — | Yes |
| 406-774 | LAMBERT | 2246 | — | Yes |
| 406-775 | EKALAKA | 2246 | — | Yes |
| 406-776 | SAVAGE | 2246 | — | — |
| 406-777 | STEVENSVL | 9636 | — | Yes |
| 406-778 | BAKER | 2246 | — | Yes |
| 406-779 | FLAXVLRURL | 2247 | — | Yes |
| 406-780 | COLUMBUS | 6564 | — | Yes |
| 406-781 | GREATFALLS | 6564 | — | — |
| 406-782 | BUTTE | 9636 | — | — |
| 406-783 | SCOBEYRURL | 2247 | — | Yes |
| 406-784 | ASHLAND | 2251 | — | Yes |
| 406-785 | NO NASHUA | 2247 | — | Yes |
| 406-786 | BROCKTON | 2247 | — | Yes |
| 406-787 | CULBERTSON | 2247 | — | Yes |
| 406-788 | GREATFALLS | 6564 | — | — |
| 406-789 | MEDICINELK | 2247 | — | Yes |
| 406-790 | CULBERTSON | 6010 | — | Yes |
| 406-791 | GREATFALLS | 9636 | — | — |
| 406-792 | BUTTE | 453F | — | Yes |
| 406-793 | OVANDO | 2235 | — | — |
| 406-794 | BILLINGS | 453F | 2006-03-15 | Yes |
| 406-795 | WIBAUX | 9636 | — | Yes |
| 406-796 | WIBAUX | 7830 | — | Yes |
| 406-797 | ANACONDA | 9636 | — | Yes |
| 406-798 | WESTSIDNEY | 2246 | — | — |
| 406-799 | GREATFALLS | 6010 | — | Yes |
| 406-800 | BRIDGER | 453F | 2013-12-11 | Yes |
| 406-802 | HAMILTON | 6564 | — | Yes |
| 406-804 | GARDINER | 453F | 2019-08-20 | Yes |
| 406-807 | EGLACIERPK | 453F | 2021-04-22 | Yes |
| 406-808 | HAVRE | 508J | — | Yes |
| 406-811 | XXXXXXXXXX | MULT | — | — |
| 406-812 | LAUREL | 453F | 2011-10-03 | Yes |
| 406-813 | BELGRADE | 7229 | 2011-09-14 | Yes |
| 406-815 | RED LODGE | 7421 | — | Yes |
| 406-818 | RED LODGE | 6010 | — | Yes |
| 406-820 | OLNEY | 453F | 2007-10-11 | 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.