All assignees
768 prefixes in 406 · initial assignments from the NANPA CO code file, 09/17/2026
| NPA-NXX | Rate center | OCN | Assigned | Pooled |
|---|---|---|---|---|
| 406-300 | KALISPELL | 792K | 2013-07-17 | Yes |
| 406-301 | MALTA | 6564 | 2008-05-06 | Yes |
| 406-302 | WOLF CREEK | 453F | 2011-10-03 | Yes |
| 406-303 | MISSOULA | 771G | 2012-04-17 | Yes |
| 406-304 | MISSOULA | 6529 | 2016-03-25 | Yes |
| 406-305 | WHSLPHRSPG | 6010 | 2010-10-20 | Yes |
| 406-306 | MANHATTAN | 453F | 2017-10-20 | Yes |
| 406-307 | CANYON CRK | 792K | 2025-03-18 | Yes |
| 406-308 | CASCADE | 6564 | 2017-09-05 | Yes |
| 406-309 | KALISPELL | 792K | 2011-07-01 | Yes |
| 406-310 | BUTTE | 7870 | — | Yes |
| 406-311 | XXXXXXXXXX | MULT | — | — |
| 406-312 | BOZEMAN | 478J | — | Yes |
| 406-313 | BOULDER | 453F | 2012-11-16 | Yes |
| 406-314 | KALISPELL | 6010 | 2004-10-21 | Yes |
| 406-315 | GREATFALLS | 443B | — | Yes |
| 406-316 | BOULDER | 453F | 2019-07-12 | Yes |
| 406-317 | MISSOULA | 073H | — | Yes |
| 406-318 | BILLINGS | 453F | 2011-02-17 | Yes |
| 406-319 | POLSON | 792K | — | Yes |
| 406-320 | ROUNDUP | 6564 | — | Yes |
| 406-321 | COLUMBUS | 6010 | — | Yes |
| 406-322 | COLUMBUS | 9636 | — | Yes |
| 406-323 | ROUNDUP | 2246 | — | Yes |
| 406-324 | HELENA | 9636 | — | Yes |
| 406-325 | BILLINGS | 732J | — | Yes |
| 406-326 | REEDPOINT | 2257 | — | — |
| 406-327 | MISSOULA | 9636 | — | — |
| 406-328 | ABSAROKEE | 2250 | — | Yes |
| 406-329 | MISSOULA | 9636 | — | — |
| 406-330 | CLINTON | 792K | — | Yes |
| 406-331 | ROUNDUP | 6564 | — | Yes |
| 406-332 | PABLO | 2235 | — | Yes |
| 406-333 | LIVINGSTON | 9636 | — | Yes |
| 406-334 | LIBBY | 6010 | 2004-05-10 | Yes |
| 406-335 | SWEETGRASS | 2248 | — | — |
| 406-336 | NOCUT BANK | 2248 | — | — |
| 406-337 | KEVINOLMNT | 2248 | — | — |
| 406-338 | BROWNING | 619J | — | Yes |
| 406-339 | ETHRIDGE | 2248 | — | — |
| 406-340 | LIMA | 6010 | — | Yes |
| 406-341 | MANHATTAN | 453F | 2020-07-06 | Yes |
| 406-342 | HYSHAM | 2251 | — | Yes |
| 406-343 | WYOLA | 2250 | — | Yes |
| 406-344 | HAVRE | 6564 | — | Yes |
| 406-345 | GLENDIVE | 7830 | — | Yes |
| 406-346 | FORSYTH | 8140 | 2002-07-11 | Yes |
| 406-347 | ROSEBUD | 2251 | — | — |
| 406-348 | HUNTLEY | 2250 | — | Yes |
| 406-349 | ALTA | 2235 | — | — |
| 406-350 | LEWISTOWN | 6010 | — | Yes |
| 406-351 | FORSYTH | 6564 | — | Yes |
| 406-352 | BOX ELDER | 2257 | — | — |
| 406-353 | HARLEM | 3310 | — | Yes |
| 406-354 | ROCK SPG | 2246 | — | — |
| 406-355 | RUDYARD | 2257 | — | — |
| 406-356 | FORSYTH | 9636 | — | Yes |
| 406-357 | CHINOOK | 2257 | — | Yes |
| 406-358 | MELSTONE | 2246 | — | — |
| 406-359 | GLENDIVE | 9636 | — | Yes |
| 406-360 | HAMILTON | 6564 | — | — |
| 406-361 | HAMILTON | 6564 | 2011-06-09 | Yes |
| 406-362 | LINCOLN | 2244 | — | — |
| 406-363 | HAMILTON | 9636 | — | Yes |
| 406-364 | HINSDALE | 2247 | — | — |
| 406-365 | GLENDIVE | 9636 | — | Yes |
| 406-366 | LEWISTOWN | 6564 | — | Yes |
| 406-367 | NO GLASGOW | 2247 | — | — |
| 406-368 | CANYON CRK | 2244 | — | — |
| 406-369 | HAMILTON | 6010 | — | Yes |
| 406-370 | MISSOULA | 6564 | — | — |
| 406-371 | BILLINGS | 7229 | 2004-07-27 | Yes |
| 406-372 | KREMLIN | 2257 | — | — |
| 406-373 | BILLINGS | 9636 | — | Yes |
| 406-374 | MOORE | 3310 | — | — |
| 406-375 | HAMILTON | 9636 | — | Yes |
| 406-376 | GILDFORD | 2257 | — | — |
| 406-377 | GLENDIVE | 7830 | — | — |
| 406-378 | BIG SANDY | 2257 | — | Yes |
| 406-379 | TURNER | 2257 | — | — |
| 406-380 | LEWISTOWN | 6564 | — | Yes |
| 406-381 | HAMILTON | 6564 | — | — |
| 406-382 | SUPERIOR | 6010 | 2003-03-18 | Yes |
| 406-383 | DODSON | 3310 | — | — |
| 406-384 | BILLINGS | 4222 | — | Yes |
| 406-385 | WESTBY | 2247 | — | Yes |
| 406-386 | HOPPILLIAD | 2257 | — | — |
| 406-387 | HUNGRYHORS | 2249 | — | Yes |
| 406-388 | BELGRADE | 9636 | — | — |
| 406-389 | HELENA | 508J | 2013-09-18 | Yes |
| 406-390 | SOUTHHAVRE | 6564 | — | Yes |
| 406-391 | CUT BANK | 6010 | — | Yes |
| 406-392 | NO WOLF PT | 2247 | — | Yes |
| 406-393 | SOMERS | 792K | 2006-03-30 | Yes |
| 406-394 | NORTHHAVRE | 2257 | — | Yes |
| 406-395 | SOUTHHAVRE | 2257 | — | Yes |
| 406-396 | MISSOULA | 6564 | 2003-11-26 | — |
| 406-397 | HINGHAM | 2257 | — | — |
| 406-398 | NORTHHAVRE | 2257 | — | Yes |
| 406-399 | SOUTHHAVRE | 6564 | — | 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.