For all cities with a population greater than one million, Thunder Bay (ON) is closest to Chicago (IL) and farthest from Perth. The closest foreign city is Chicago (IL) and the farthest domestic city is Calgary (AB). See below for the top 5 closest and farthest cities (domestically, internationally and by continent) and to see which cities, if any, Thunder Bay (ON) is the closest and farthest to. Filter to include all cities over 100k, 500k or 1 million in population.