Area codes 450 and 579

Area codes 450 and 579 are telephone area codes in the Canadian province of Quebec, encompassing the off-island suburbs of Montreal, which is served by area codes 514 and 438. Among the cities served by area code 450 are Longueuil and Laval. The communities of Ormstown, Huntingdon, Boucherville, Varennes, Roussillon, Joliette, Saint-Hyacinthe, Granby, Chambly, Saint-Jean-sur-Richelieu and Vaudreuil-Dorion are also part of this area code. The 450 area code 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 have +1-450-451-xxxx numbers from the Rigaud phone exchange.

514 had served the entire Montreal area for over half a century. However, by the mid-1990s it was on the verge of exhaustion due to Montreal's rapid growth and Canada's inefficient system of number allocation. All Canadian competitive local exchange carriers are allocated blocks of 10,000 numbers for every rate centre where they plan to offer service, even in the smallest hamlets. Even though most rate centres don't need nearly that many numbers, a number can't be reallocated elsewhere once assigned to a carrier and rate centre. This resulted in thousands of wasted numbers. By the latter years of the 20th century, this made a second area code necessary in Canada's second-largest toll-free calling zone.

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