+1 579 area code (Quebec): Granby, Joliette, St-Jerome

The range at a glance

+1 579 in NANPA’s area code report

+1 579 is a North American area code for Quebec, in service since 21 August 2010, sharing its area with 354, 450, per NANPA’s NPA report of 20 October 2026. NANPA names 450 as the code it came from: the 3 codes of the overlay serve one area, so a new number there can get any of them.

Exchange areas with the most allocated codes (CNAC)

Each central office code is assigned for a exchange area, the regulator’s billing area for it, named after a town or exchange. It is not where a subscriber is: mobile and VoIP numbers are used anywhere, and a ported number keeps its exchange area. The 645 assigned codes in 579 are spread over 126 exchange areas.

Codes assigned in the last 12 months, and codes not yet in service

The CNAC’s central office code file of 18 October 2026 lists 7 codes in 579 assigned in the 12 months to 18 October 2026. Not yet in service: 1 code. The CNAC’s table is read at code level only. A code not yet in service is waiting for its effective date; a reassigned block can hold numbers used before. Original allocation, not who serves a number today.

Blocks in the regulator's table

Each block is a 6-digit prefix of the national number. A number in an allocated block is assignable; in an unassigned block no carrier can have a subscriber, so the lookup answers unassigned_block for it, except a number in a range reserved for fiction (is_fictional), which answers valid even where the regulator lists its block as protected. Of the allocated blocks, 4.7% belong to a wireless carrier, 45.7% to a virtual-number wholesaler or VoIP provider, and 49.6% to a holder whose name settles neither.

Who the blocks were allocated to

The holders as the regulator lists them, by number of allocated blocks. Allocation is not service: a ported number keeps its original block, so a holder here may no longer serve a given number. The last row adds up every other allocated block in the table: the smaller holders and any holder this page does not name.

What each network brand’s legal entities hold across the whole table, counted in numbers: Telus, Fibernetics, Bell, Vidéotron, Iristel, Rogers.

All 645 assigned central office codes in 579

Each row is a central office code (the three digits after the area code) as the CNAC’s central office code file lists it: the exchange area it is assigned for, the network brand of the code holder where the brand map knows one, and the date it was assigned where the file gives one. Original allocation, not who serves a number today: a ported number keeps its code. There is no page per code.

How to read this page

Everything above comes from three public sources: the numbering metadata, which names the zones and the line types of the range and, outside North America, its place; and the regulator's allocation table, which lists each block's status and holder and, in North America, the rate centres the place is named from. NANPA’s NPA report adds what it says about the whole area code: its state or province, the codes sharing its area, when it went into service, local dialling and relief planning. None of them knows who serves a number today, whether a handset is switched on, or who owns or answers it. Spaw reports what the tables say and names the dataset and version behind every answer.

More area codes in Canada

• +1 506
• +1 514
• +1 519
• +1 548
• +1 581
• +1 584
• +1 587
• +1 604
• All area codes in Quebec
• All area codes in Canada
• New and upcoming North American area codes
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cnac-co-codes 2026-10-18 · nanpa-npa-report 2026-10-20 · newest data dated 2026-10-20 · about the regulator’s table