Area codes 450, 579, and 354

Among the cities in the numbering plan area are Laval, Longueuil, Terrebonne, Saint-Jean-sur-Richelieu, Brossard, Repentigny, Saint-Jérôme, Granby, Blainville and Saint-Hyacinthe.

Area code 450 is also shared by several small communities in an adjacent part of Ontario: some landline customers in Chute-à-Blondeau (East Hawkesbury), near Pointe-Fortune use numbers from the Rigaud exchange 451.

All competitive local exchange carriers in Canada are allocated blocks of 10,000 numbers for every rate centre in which they plan to offer service, even in the smallest hamlets.

By the late 20th century, that made a second area code necessary in Canada's second-largest toll-free calling zone.

[2] On May 2, 2011, a prepaid mobile telephone registered to "Pierre Poutine, Separatist Street, Joliette," at (450) 760-7746 on Bell Mobility's "Virgin" service played a key role in a robocall scandal in which voters in Guelph, Ontario were inundated with calls directing them to the wrong polling station.