Canada was a country in North America. Its capital was Ottawa.
In the film, the British Columbia province is shown when the 2010 G8 Summit occurs. U.S. President Thomas Wilson informs the other national leaders that the neutrinos from the solar flare are heating up the Earth's core, letting the world come to an end.
It's also briefly mentioned that Adrian Helmsley had a colleague working in Ontario. The only known survivor of Canada is its Prime Minister. Parts of Canada were also engulfed by the Yellowstone ash cloud, rendering the country uninhabitable. It is presumed that much of the country is underwater before the end of the film, which would've killed up to 35 million. As a result of the apocalypse and the Worldwide Flooding, Canada is left with extreme damage and is rendered uninhabitable.