Possums have been in southern Ontario all of my life and they've been in Toronto for at least 10 years. I used to see one every year or two, lately I run into a few a year. Raccoons still have them beat 100 to 1 though. 
Apparently the Virginia opossum is the only species in Canada and only in southern Ontario.
Apparently the Virginia opossum is the only species in Canada and only in southern Ontario.