The Greater Toronto Area Runs Canada In the dying days of every election campaign, Canada looks to its most populous province to glean insight into who will form the next federal government.
And when predicting who will win, the most important region in Ontario is easily the Greater Toronto Area (GTA). If a party hopes to form government, it has to win multiple seats there.
Unfortunately for Erin O’Toole and the Conservatives, Ontario has been a historically Liberal-leaning province, with fairly well-established voting patterns since the turn of the century:
https://ipolitics.ca/2021/09/08/gta-federal-election-2021/