Phone prefixes in Markham, ON
Markham, ON is a rate centre in the Canadian numbering plan. CNAC records 81 in-service prefixes there, held by 17 carriers and spread across 4 area codes (365, 289, 905, 742).
Background reading: Canadian area codes, overlays, and what a 416 number actually tells you · Caller ID spoofing, STIR/SHAKEN, and how to actually block calls in Canada
In numbers
- In-service prefixes
- 81
- Telephone numbers covered
- 810,000
- Carriers
- 17
- Area codes
- 4
- Provinces and territories
- 1
- First assignment
- January 31, 2000
- Most recent assignment
- December 1, 2025
Area codes
Who holds these numbers
Iristel Inc. holds the largest share at 48 prefixes, 59.3% of the total, ahead of 16 other carriers.
| Carrier | Prefixes | Share | First assigned |
|---|---|---|---|
| Iristel Inc. | 48 | 59.3 % | 2007 |
| Rogers Communications Canada Inc. (Cable) | 6 | 7.4 % | 2000 |
| Bell Canada | 5 | 6.2 % | 2003 |
| Fibernetics Corporation | 5 | 6.2 % | 2007 |
| TELUS Integrated Communications | 3 | 3.7 % | 2015 |
| IXICA Communications Inc. | 2 | 2.5 % | 2017 |
| InnSysVoice Corp | 2 | 2.5 % | 2014 |
| Beanfield Technologies Inc. | 1 | 1.2 % | 2021 |
| Comwave Networks | 1 | 1.2 % | 2013 |
| Distributel | 1 | 1.2 % | 2016 |
| ExaTEL Inc. | 1 | 1.2 % | 2014 |
| FGLTEL Inc. | 1 | 1.2 % | 2022 |
| ISP Telecom Inc. | 1 | 1.2 % | 2006 |
| Primus Telecommunications Canada Inc. | 1 | 1.2 % | 2008 |
| Rogers Communications Canada Inc. | 1 | 1.2 % | 2019 |
| TekSavvy Solutions Inc | 1 | 1.2 % | 2021 |
| Zayo Canada Inc. | 1 | 1.2 % | 2012 |
Allocated prefixes
All 81 in-service prefixes, grouped by rate centre.
Markham, ON
289-301 · 289-306 · 289-307 · 289-378 · 289-451 · 289-469 · 289-507 · 289-554 · 289-590 · 289-661 · 289-666 · 289-800 · 289-818 · 289-846 · 289-859 · 289-872 · 365-360 · 365-361 · 365-362 · 365-363 · 365-376 · 365-379 · 365-412 · 365-413 · 365-414 · 365-430 · 365-461 · 365-462 · 365-463 · 365-464 · 365-478 · 365-479 · 365-480 · 365-481 · 365-482 · 365-483 · 365-484 · 365-486 · 365-487 · 365-509 · 365-549 · 365-600 · 365-635 · 365-636 · 365-654 · 365-655 · 365-687 · 365-689 · 365-690 · 365-691 · 365-692 · 365-693 · 365-694 · 365-695 · 365-696 · 365-697 · 365-698 · 365-699 · 365-700 · 365-873 · 365-874 · 365-899 · 365-955 · 365-960 · 365-970 · 365-980 · 365-990 · 742-377 · 742-771 · 742-777 · 905-201 · 905-202 · 905-205 · 905-209 · 905-294 · 905-350 · 905-368 · 905-471 · 905-472 · 905-554 · 905-910
Nearby rate centres
| Rate centre | Province | Prefixes | Carriers |
|---|---|---|---|
| Toronto | ON | 2,141 | 24 |
| Ottawa-Hull | ON | 441 | 20 |
| Hamilton | ON | 221 | 23 |
| London | ON | 217 | 23 |
| Kitchener-Waterloo | ON | 164 | 21 |
| Windsor | ON | 133 | 20 |
| Brampton | ON | 116 | 20 |
| Oshawa | ON | 110 | 20 |
| St. Catharines-Thorold | ON | 107 | 19 |
| Barrie | ON | 95 | 18 |
| Oakville | ON | 90 | 18 |
| Kingston | ON | 83 | 19 |
Allocation source: Canadian Numbering Administrator (CNAC), the registry that records which carrier a central-office code was originally issued to. An allocation says who was issued the prefix, not who serves the number today: numbers can be ported between carriers, and caller ID can be spoofed outright.