Area code 406 is the telephone area code covering the entire state of Montana. It has been Montana's area code since area codes were created in 1947.
As of 2013, there were 1.7 million lines served by 47 carriers; all but two wireline providers support local number portability (the exceptions are small rural independents Hot Springs Telephone Company and Northern Telephone Cooperative). Sufficient available codes for new exchanges in the 406 area code exist to meet anticipated demand until 2019; number pooling has been implemented in response to increased demand and inefficient use of 406 numbering resources.
Absarokee: 328, 985Alberton: 722Alta: 349Alzada: 828, 938Anaconda: 559, 560, 563, 691, 797Arlee: 726Ashland: 784, 983Augusta: 562Avon: 492Bainville: 769Baker: 778, 891, 956, 978Belfry: 664Belgrade: 388, 813, 924Belt: 277Bigfork: 420, 837Big Sandy: 378Big Sky: 993, 995, 999Big Timber: 930, 931, 932, 936Billings: 200, 206, 208, 237, 238, 245, 247, 248, 252, 254, 255, 256, 259, 272, 281, 294, 318, 325, 371, 373, 384, 435, 534, 545, 591, 598, 601, 606, 620, 647, 651, 652, 655, 656, 657, 661, 670, 671, 672, 690, 694, 696, 697, 698, 702, 794, 839, 850, 855, 860, 861, 867, 869, 876, 894, 896, 927, 969Birney: 984Bloomfield: 583Boulder: 225, 313Box Elder: 352Bozeman: 209, 219, 312, 404, 414, 451, 522, 539, 548, 551, 556, 570, 577, 579, 580, 581, 582, 585, 586, 587, 589, 595, 599, 600, 602, 624, 898, 916, 920, 922, 994Brady: 753Bridger: 662, 800Broadus: 436, 935Broadview: 667Brockton: 786Browning: 338, 573Busby: 592Butte: 221, 299, 310, 479, 490, 491, 494, 496, 497, 498, 533, 565, 593, 723, 782, 792Canyon Creek: 368Carlyle: 588Carter: 734Cascade: 468Charlo: 644Chester: 759Chinook: 357Choteau: 466Circle: 485, 974Clinton: 330, 825Clyde Park: 686Colstrip: 213, 720, 740, 748, 749Columbia Falls: 892, 897Columbus: 290, 298, 321, 322, 780Condon: 754Conrad: 271, 278, 289, 505, 576Cooke City: 838Crooked Creek: 484Culbertson: 514, 787, 790Custer: 856Cut Bank: 229, 391, 845, 873Dagmar: 483Darby: 821Decker: 757Deer Lodge: 415, 645, 846Denton: 567Devon: 432Dillon: 596, 660, 683, 865, 925, 960, 988Divide: 267, 553Dixon: 246Dodson: 383Drummond: 288Dupuyer: 472Dutton: 476East Conrad: 627East Glacier Park: 226Ekalaka: 775, 975Elmo: 631, 849Ennis: 682Ethridge: 339Eureka: 296Eureka rural: 297, 882, 889Fairfield: 467Fairview: 742, 747Fallon: 486Finley Point: 571, 887Flaxville: 474Flaxville rural: 779Forsyth: 201, 346, 351, 356, 729Fort Benton: 621, 622Fort Peck: 526Fort Shaw: 264Fort Smith: 666Frazer: 695Frenchtown: 508, 626Froid: 766Froid rural: 963Fromberg: 668Gallatin Gateway: 518, 763Gardiner: 848Geraldine: 737Geyser: 735Gildford: 376Glasgow: 228, 230, 263, 831, 942Glendive: 345, 359, 365, 377, 948, 987Glentana: 724Grant: 681Grass Range: 428, 928Great Falls: 205, 216, 217, 231, 268, 315, 403, 452, 453, 454, 455, 564, 590, 604, 727, 731, 750, 760, 761, 770, 771, 781, 788, 791, 799, 836, 866, 868, 870, 878, 899, 923, 952, 964, 965Hamilton: 360, 361, 363, 369, 375, 381, 802, 961Hardin: 623, 629, 638, 665, 679, 699, 953Harlem: 353Harlowton: 632Harrison: 685Haugan: 678Havre: 262, 265, 808, 879, 945Hays: 673Helena: 202, 204, 227, 324, 389, 410, 417, 422, 430, 431, 437, 438, 439, 440, 441, 442, 443, 444, 447, 449, 457, 458, 459, 461, 465, 475, 495, 502, 513, 555, 558, 594, 603, 634, 841, 933, 992, 996Highwood: 733Hingham: 397Hinsdale: 364Hobson: 423Hopp Illiad: 386Hot Springs: 741Hungry Horse: 387, 929Huntley: 348Hysham: 342Jackson: 834Joliet: 905, 962Joplin: 292Jordan: 557, 977Judith Gap: 473Kalispell: 212, 249, 250, 253, 257, 260, 261, 270, 300, 309, 314, 407, 471, 607, 751, 752, 755, 756, 758, 858, 871, 885, 890Kevin-Oilmont: 337Kremlin: 372Lakeside: 709, 844Lambert: 774, 914Lame Deer: 477Larslan: 725Laurel: 530, 628, 633, 743, 812Lavina: 636Lewistown: 350, 366, 380, 535, 538, 707, 708, 968Libby: 283, 291, 293, 334, 400Lima: 276, 340Lincoln: 362Lindsay: 584Livingston: 220, 222, 223, 224, 333, 823, 946Lodge Grass: 639Loma: 739Malta: 301, 654, 680Manhattan: 282, 284Marion: 854, 991Martinsdale: 572Medicine Lake: 789Melrose: 835Melstone: 358Melville: 537Miles City: 232, 233, 234, 851, 852, 853, 874, 934, 944, 951Missoula: 203, 207, 214, 215, 218, 239, 240, 241, 243, 251, 258, 273, 274, 303, 317, 327, 329, 370, 396, 493, 523, 529, 531, 532, 540, 541, 542, 543, 544, 546, 549, 550, 552, 721, 728, 829, 830, 880, 926Molt: 669Moore: 374Musselshell: 947Nashua: 746Neihart: 236North Broadus: 554North Cut Bank: 336North Frannie: 764North Glasgow: 367North Hinsdale: 648North Nashua: 785North Parkman: 643, 659North Poplar: 448North Havre: 394, 398North Ryegate: 575North Wolf Point: 392Noxon: 847Olney: 820, 881Opheim: 762Outlook: 895Ovando: 793Pablo: 275, 332, 675Peerless: 893Pendroy: 469Philipsburg: 859Plains: 826Plentywood: 765Plevna: 772, 971Polson: 319, 872, 883, 884Pompey's Pillar: 875Poplar: 768Potomac: 244Power: 463Rapelje: 663Raynesford: 738Red Lodge: 425, 426, 445, 446, 818Reed Point: 326Reserve: 286Richey: 773, 979Ridge: 767Rock Springs: 354Ronan: 528, 676, 833Rosebud: 347Roundup: 320, 323, 331, 913Roy: 464, 954Rudyard: 355Ryegate: 568Saco: 527Saint Ignatius: 744, 745, 824Saint Mary: 732Savage: 776Scobey: 487, 688Scobey rural: 783Seeley Lake: 210, 499, 677Shelby: 424, 434, 450, 460, 470, 597, 966Sheridan: 842Sidney: 433, 478, 480, 482, 488, 489, 630, 943, 973Silvertip: 574, 840Somers: 393, 857South Alberton: 864South Broadus: 427South Chester: 456South Miles City: 421, 981South Havre: 390, 395, 399South Malta: 658South Wolf Point: 525, 915Stanford: 566Stevensville: 625, 777Stockett: 736Saint Regis: 269, 280, 649Sunburst: 561, 937Superior: 382, 515, 822Swan Lake: 612, 886Sweetgrass: 335Terry: 635, 637, 957Thompson Falls: 242, 615, 827Three Forks: 285, 616Townsend: 266, 521, 949, 980Troy: 295Turner: 379Twin Bridges: 684Valier: 279Victor: 642Virginia City: 843Valley Industrial Park: 524Warm Springs: 693West Beach: 877Westby: 385West Camp Crook: 972West Glacier: 888West Glendive: 687, 939, 941, 989West Sidney: 798West Squaw Gap: 569West Yellowstone: 640, 641, 646Whitefish: 730, 862, 863Whitehall: 287Whitewater: 674White Sulphur Springs: 305, 547Wibaux: 795, 796Wilsall: 578Winifred: 462Winnett: 429Wisdom: 689Wise River: 832Wolf Creek: 235, 302Wolf Point: 650, 653Worden: 967Wyola: 343Yellow Bay: 692, 982Premium numbers: 976On December 10, 2008, Google's Gmail Blog announced that SMS messages could be sent from inside Gmail. The messages are sent from numbers in the 406 area code. Each number is unique and can be bookmarked in your phone for replies or future use.
Google also employs the use of area code 406 for the assignment of reply-to or callback numbers for Google Voice's customers' contacts.