The numbering plan area surrounds the city of Toronto (area codes 416/647/437), leading locals to refer to the primarily suburban cities surrounding Toronto as "the 905" or "905 belt". It is bound by the 519/226/548 overlay area in the west, 705/249/683 in the north, 613/343 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.
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 country code +52, these arrangement were continued into the 1980s. The assignment of 905 was finally officially withdrawn by February 1, 1991.
By October 1991, area code 905 had been assigned to relieve exchanges in 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, but 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. However, the number allocation system did not allow number blocks to be reassigned from smaller rate centres to the Toronto rate centre. The proliferation of cell phones, pagers, fax machines, and dial-up Internet connections made it obvious that the Golden Horseshoe needed another area code.
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 dialing 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 customers to change their numbers for the second time in less than a decade and forced the reassignment of cellphone numbers. For the same reason, 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 dialing plan.[4] Permissive seven-digit or ten-digit dialing 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.[5][6]
A numbering plan exhaust analysis of 2020 projected an exhaust date of March 2023 for the numbering plan area.[7]
Area code 537 was reserved as a fifth area code for the region in November 2022.[8]
The term the 905orthe 905 belt is used to describe the suburban areas of the Greater Toronto Area,[9] 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.[10] Canadian rapper Maestro rendered homage to the area code in his song "416/905 (TO Party Anthem)"; "TO" (pronounced "T" "O") 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.[citation needed] 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.[citation needed] In both cases, the opposition party was elected to government with strong backing of the 905 region.[citation needed] 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[11] and the region has become a political bellwether.[12] In the end, most 905 ridings were won by the Liberals over the Conservatives.[13] The Liberals ultimately beat the Conservatives and formed a minority government with the support of the 905.[14]
^"905 region to add new area code". CBC News. April 13, 2010. Retrieved April 18, 2010. The area around Toronto is known colloquially as "the 905," after the area code that was added in 1993 and covers such areas as Mississauga and Niagara Falls.
