Phone prefixes in Lachute, QC

In numbers

In-service prefixes

18

Telephone numbers covered

180,000

Carriers

8

Area codes

3

Provinces and territories

1

First assignment

February 21, 2002

Most recent assignment

August 21, 2025

Lachute’s share of its area codes

Within area code 579, Lachute accounts for only 9 of 644 prefixes (1.4%): the code is dominated by Granby and spread over 126 rate centres. Within area code 450, Lachute accounts for only 8 of 775 prefixes (1.0%): the code is dominated by Granby and spread over 129 rate centres. Within area code 354, Lachute accounts for only 1 of 56 prefixes (1.8%): the code is dominated by Valleyfield and spread over 49 rate centres.

Who holds these numbers

Videotron Ltd. holds the largest share at 5 prefixes, 27.8% of the total, ahead of 7 other carriers. Code by code: in 579, Iristel Inc. leads with 4 of 9 prefixes ahead of 4 others; in 450, Videotron Ltd. leads with 3 of 8 prefixes ahead of 3 others; Cogeco Connexion Inc. is the only holder in 354. No carrier holds prefixes in every one of Lachute’s 3 area codes, while 6 appear in just one.

Wireless and wireline

4 of Lachute’s 18 prefixes (22.2%) are held by carriers whose registered name marks a wireless business: Bell Mobility and TELUS Mobility. Wireline prefixes still outnumber them, carried by Videotron Ltd, Iristel Inc, Bell Canada and Cogeco Connexion Inc. This is a sort by name, not a licence lookup, and a mobile prefix may have been ported to another network since.

How the allocation was built up

Lachute’s dated assignments run from 2002 to 2025. The busiest period was 2015–2019, when 7 prefixes went to 4 carriers. 2 prefixes (11%) carry no date in the register: these are the historic pre-1999 assignments, the wireline bedrock of the rate centre. Since 2020 another 3 prefixes have been added, so the rate centre is still growing.

Lachute’s oldest prefixes, the ones the register leaves undated, belong to Bell Canada: this carrier made up the landscape before competition arrived. The first dated assignment went to TELUS Mobility in 2002. The most recent arrivals are Cogeco Connexion Inc. (2025), ISP Telecom Inc. (2022) and TELUS Quebec (2016), a sign that new carriers are still asking for numbers in Lachute.

Lachute has only 18 prefixes, or 180,000 numbers: a small rate centre, where the arrival of a single new carrier visibly changes the landscape.

No single carrier dominates Lachute: the leader, Videotron Ltd., holds only 27.8% of the prefixes against 7 competitors, a sign of a highly fragmented market where cable companies, mobility brands and VoIP providers weigh as much as the incumbent.

Allocation is mature: only 18.8% of the dated prefixes are less than ten years old, most having been handed out in 2015–2019, and 2 prefixes go back to the undated monopoly era. New Lachute numbers mostly come out of blocks that were assigned long ago.

2 undated in the register.

Dialling a Lachute number

Lachute is served by 3 overlaid area codes (579, 450 and 354). A 354 number is no more “out of town” than a 579 one; from abroad, dial +1 and the full ten digits.

The numbering neighbourhood

Lachute shares area codes 579, 450 and 354 with at least 20 other rate centres, including Granby, Joliette, St-Jerome, St-Hyacinthe, Longueuil, Ste-Therese, St-Lambert and Sorel. The largest of them, Granby, holds 52 prefixes in 354, 450 and 579; the smallest on the list, St-Vincent-de-Paul, has just 17.

What a Lachute number tells you

A number attached to Lachute tells you that its prefix was issued to a carrier for this rate centre in Quebec, most often Videotron Ltd.. It does not tell you where the handset is today: a subscriber may have ported the number to any of the 8 carriers present here or to a VoIP service usable anywhere. Nor does it tell you who is calling: caller ID can be spoofed, and a Quebec area code is easy to borrow to look local.

Reading a register entry for Lachute: code 579-366 is recorded for Videotron Ltd., so every 579-366-XXXX number (10,000 possible) descends from that assignment. “Lachute, Quebec” there names a rate centre, not a municipality, and several area codes overlay it.

Every Lachute prefix

Each row is an in-service central-office code recorded for Lachute, with its original holder and year of assignment.

Allocated prefixes

All 18 in-service prefixes, grouped by rate centre.

Elsewhere in Quebec