[votr]

If Waterloo is part of Toronto, you may as well count in Hamilton, Oakville, and Milton as well. Hell, throw in Niagara Falls.

[kmanraj]

Those cities are actually part of a geographic region called the Golden Horseshoe Area, which is more comparable to Census Statistical Areas in the US (like the SF Bay Area, Baltimore-Washington Area, and Chicagoland).

[astrodust]

It's called the "Greater Toronto Area" for a reason.