The 905 area code serves a large region in southern Ontario, Canada. It includes not only the cities of Mississauga, Oakville, Burlington, and Hamilton, but also several other municipalities. Some of the other areas within the 905 region include:
- Markham
- Richmond Hill
- Vaughan
- Ajax
- Whitby
- St. Catharines
- Niagara Falls
- Welland
- Milton
This area code covers a mix of suburban communities and urban centers, many of which are part of the Greater Toronto Area (GTA). The region has grown significantly over the years, leading to the introduction of additional area codes (such as 289 and 365) to accommodate the increasing demand for phone numbers.