Area codes 905, 289, 365, and 742

Area codes 905, 289, 365, and 742 are telephone area codes in the North American Numbering Plan (NANP) for the Golden Horseshoe region that surrounds Lake Ontario in Southern Ontario, Canada. The numbering plan area (NPA) comprises (clockwise) the Niagara Peninsula, the city of Hamilton, the regional municipalities of Halton, Peel, York, Durham, and parts of Northumberland County, but excludes the City of Toronto.

The four area codes form an overlay numbering plan for the same geographic region, where area code 905 was established in October 1993 in an area code split from area code 416. When 289 was overlaid on June 9, 2001, all local calls required ten-digit dialling. On April 13, 2010, the Canadian Radio-television and Telecommunications Commission (CRTC) introduced another overlay code, area code 365, which became operational on March 25, 2013. Area code 742 was added to the overlay on October 16, 2021.

The numbering plan area surrounds the city of Toronto (area codes 416/647/437/942), leading locals to refer to the primarily suburban cities surrounding Toronto as "the 905" or "905 belt". It is bounded by the 519/226/548/382 overlay area in the west, 705/249/683 in the north, 613/343/753 in the east, and Western New York State's 716/624 area on the eastern prong of the Niagara Peninsula. The incumbent local exchange carrier is Bell Canada.

History From the 1960s, area code 905 was assigned for special call routing arrangements to Mexico City during the time when Mexico was expected to join the North American Numbering Plan. After establishing its own numbering plan with telephone country code 52, these arrangement were continued into the 1980s. The assignment of 905 was finally withdrawn by February 1, 1991.

The area code 905 was introduced on October 4, 1993 for the Golden Horseshoe, which was and still is Canada's largest toll-free calling zone. The Golden Horseshoe's explosive growth in the second half of the 20th century and the corresponding expansion of telecommunications service would have made another area code necessary in any event. However, the timetable was advanced because Canada's system of number allocation does not use number pooling as a relief measure. Instead, each competitive local exchange carrier (CLEC) is assigned blocks of 10,000 numbers, which correspond to a single three-digit prefix, for every rate centre in which it plans to offer service. Most rate centres do not need that many numbers to serve their customers. However, excess numbers cannot be reassigned elsewhere once they are assigned to a rate centre.

The problem was not as severe in the Golden Horseshoe as in the rest of Canada since numbers have tended to be used up fairly quickly. The proliferation of cell phones, pagers, fax machines, and dial-up Internet connections made it obvious that the Golden Horseshoe would need another area code. However, the timetable for relief was significantly advanced since it was not possible for number blocks to be reassigned from the Golden Horseshoe's smaller rate centres to the Toronto rate centre.

Automatic number identification (ANI) in some central office switching systems in the numbering plan area started operation on October 11, 1992. The new area code entered service on October 11, 1993. Permissive dialling of 416 continued across the Golden Horseshoe until January 1, 1994. However, portions of the 905 territory have remained ever since a local call to Toronto.

The creation of area code 905 was intended as a long-term solution. However, five years after its introduction, area code 905 was close to exhaustion far sooner than anticipated, again due to the proliferation of cell phones and pagers. By 1999, the CRTC had established an ad hoc committee to study code relief planning for area code 905. A split of the NPA was considered, with various options being presented: a geographic split by municipality (either two-way or three-way) a geographic split of concentric rings around Toronto a realignment of NPA boundaries a distributed overlay

The overlay option was chosen because it would cause the least disruption and was supported by all of the carriers. A split would have forced some customers to change their numbers for the second time in less than a decade, which would have entailed en masse reprogramming of cell phones. Additionally, an overlay was seen by this time as an easy workaround for the number allocation problem. Around the same time, Toronto was overlaid with area code 647 (and later 437).

NPA 289 was approved by the CRTC on August 15, 2000 in Order CRTC 2000–772. The order had the CRTC direct Bell Canada to implement a ten-digit local dialling plan.Order CRTC 2001-840 (copy archived February 3, 2004) Permissive seven-digit or ten-digit dialling for 905-customers began on April 7, 2001, before the in-service date for 289 of June 9, 2001.

The Golden Horseshoe's continued growth caused area code 365 to be assigned for further relief on March 25, 2013. Also, area code 742 was assigned on October 16, 2021.

A numbering plan exhaust analysis of 2020 projected an exhaust date of March 2023 for the numbering plan area.

Area code 537 was reserved as a fifth area code for the region in November 2022.

In popular culture The term the 905 or the 905 belt is used to describe the suburban areas of the Greater Toronto Area, while Toronto proper is referred to as the 416. The term 905er is often used pejoratively by Toronto residents to refer to suburban residents outside the city.Toronto, Cultural Tips, Places of a Lifetime, Travel, Photography - National Geographic Canadian rapper Maestro rendered homage to the area code in his song "416/905 (TO Party Anthem)"; "TO" (pronounced "teeyo") is an abbreviation or nickname locals use when referring to the city of Toronto. In June 2015, Maple Leaf Sports & Entertainment announced the formation of an NBA Development League team for the Toronto Raptors based in Mississauga called Raptors 905.

The term has been used in the context of Canadian politics, where the 416 is a stronghold of Liberals and NDP, whereas the 905 (excluding Hamilton) historically had strong ties to the Progressive Conservative Party. The region has, however, backed opposition parties as a protest vote, including both the NDP in the 1990 provincial election and the Liberals in the 2003 provincial election, as a backlash to the incumbent government. In both cases, the opposition party was elected to government with strong backing of the 905 region. The 2011 federal election saw the 905 region become predominately represented by candidates of the Conservative Party of Canada, while one third of the 416 ridings were won by Conservatives, many through vote splitting between the Liberals and NDP. In the 2019 federal election, the Liberals successfully held all 25 ridings in the 416, which they won in 2015. However, the parties were fighting over control over the 905 as, historically, winning the 905 is key to parties forming government and the region has become a political bellwether. In the end, most 905 ridings were won by the Liberals over the Conservatives. The Liberals ultimately beat the Conservatives and formed a minority government with the support of the 905.

Rate centres and central office codes Ajax-Pickering: (289)-200 224 229 255 275 277 314 315 372 387 388 403 417 422 423 460 482 484 533 539 545 591 608 624 631 660 733 734 744 882 892 913 915 923 980 986 987 988, (365)-275 300, (905)-231 239 250 391 409 420 421 422 423 424 426 427 428 492 509 550 619 621 622 626 683 686 706 744 767 831 837 839 903 995 999 Aurora: (289)-221 258 380 466 552 614 648 796 802 840 879 894 984 995, (365)-500 803, (905)-222 395 503 713 717 726 727 750 751 758 841 900 Beeton: (289)-415 899 970, (365)-560 901, (905)-724 729 748 801 909 Bethesda: (289)-262 615, (365)-501, (905)-504 888 Blackstock: (289)-702, (365)-408, (905)-986 Bowmanville: (289)-223 276 513 626 703, (365)-401, (905)-419 623 697 Bradford: (289)-464 831, (365)-266 900 (905)-551 775 778 Brampton is divided into the following local rate centres: Brampton (289)-201 233 298 323 325 401 406 410 418 498 499 505 541 544 569 632 654 720 747 748 752 764 801 864 889 900 901 946 948, (905)-216 226 230 291 450 451 452 453 454 455 456 457 458 459 460 463 487 488 494 495 497 499 500 595 598 654 759 781 782 783 789 790 791 792 793 794 796 798 799 840 846 861 863 866 867 872 874 901 965 970 Castlemore: (289)-324 749 916, (365)-201, (905)-200 204 794 913 915 Snelgrove: (289)-954, (365)-203, (905)-843 996 Burlington: (289)-208 230 245 266 288 293 313 337 348 419 427 598 635 636 707 714 741 745 787 798 812 816 828 861 938 962 977 983, (365)-999, (905)-220 315 319 320 331 332 333 335 336 340 407 592 630 631 632 633 634 635 637 638 639 681 802 Caledon is divided into the following local rate centres: Bolton: (289)-206 461 487 503 616 651 875 906, (365)-502, (905)-533 857 951 Caledon: (289)-824 908 961 966, (365)-200, (905)-584 586 587 588 757 838 843 860 996 Palgrave: (289)-546 594, (365)-516, (905)-583 880 Victoria: (289)-955 967, (365)-204, (905)-838 998 Caledonia: (289)-284 285 523 528 751 757 960, (905)-765 Campbellville: (289)-458 630 692, (365)-304, (905)-854 Castleton: (905)-344 Cayuga: (289)-370 516 603 736, (905)-772 Claremont: (289)- 462, (365)-503 650, (905)-408 490 649 Cobourg: (289)-215 251 252 435 677 691 771 829, (365)-400, (905)-207 269 372 373 375 376 377 396 Colborne: (289)-265, (905)-355 Cold Springs: (905)-342 Dunnville: (289)-209 330 331 332 369 377 381 433 518 604 738 761 972 973, (365)-651, (905)-229 701 774 East Gwillimbury is divided into the following local rate centres: Mount Albert: (289)-465 534 662, (365)-510, (905)-473 557 Queensville: (289)-549, (365)-529, (905)-478 589 Fisherville: (289)-601, (905)-779 Fort Erie is divided into the following local rate centres: Fort Erie (289)-250 303 320 321 322 476 599 762 (365)-801, (905)-871 991 992 993 994 Ridgeway: (289)-876 (905)-894 Stevensville: (289)-397, (905)-382 Garden Hill: see Port Hope Georgetown: (289)-344 349 428 642 694 790 839 890 891 924 935, (365)-302, (905)-702 703 873 877 Gormley: (289)-486 746, (365)-504, (905)-284 400 534 887 927 Grafton: (905)-349 Grimsby: (289)-205 235 336 447 455 493 754 770 797, (905)-309 945 Hagersville: (289)-282 283 524 758 784, (905)-768 Hamilton is divided into the following local rate centres: Ancaster: (289)-204 239 346 443 445 450 495 515 735 739 855 902, (905)-304 648 Binbrook: (289)-286 287 424 522 568 743 756, (905)-692 Dundas: (289)-238 345 446 494 517 737 753 858, (905)-627 628 Freelton: (289)-609 679 693, (365)-301, (905)-659 Hamilton: (289)-237 244 246 253 260 263 308 309 335 339 358 382 389 391 396 408 425 426 439 440 441 442 456 489 492 520 527 551 556 639 659 667 674 678 680 682 683 684 689 698 700 750 755 766 768 769 773 774 775 776 778 779 780 788 799 808 827 860 877 880 887 919 920 921 922 925 931 933 941 949 975 978 994, (365)-317 888, (905)-218 253 296 297 308 312 314 317 318 379 381 383 385 387 388 389 390 393 481 496 512 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 531 536 537 538 540 541 543 544 545 546 547 548 549 560 561 570 572 573 574 575 577 578 581 645 661 667 719 730 741 745 746 769 777 807 818 865 869 870 902 906 912 920 921 923 928 929 961 962 963 966 971 972 973 974 975 977 978 979 981 Mount Hope: (289)-280 281 491 525 759 791 866, (905)-679 Stoney Creek: (289)-203 448 490 526 656 760 765 792 965, (905)-594 636 662 664 930 Waterdown: (289)-352 431 619 718 767 895, (905)-689 690 Winona: (289)-649 794, (905)-643 Hampton: (289)-706, (365)-403, (905)-263 445 Keswick: (289)-528, (365)-505, (905)-476 535 656 700 989 King Township is divided into the following local rate centres: King City: (289)-207 467 530 618 621 874 907, (365)-506, (905)-539 833 Nobleton: (289)-463 542 620 658 664, (365)-514, (905)-558 859 Schomberg: (289)-318 557 592, (365)-520, (905)-590 939