Thunder Bay City in Ontario, Canada is the most populated municipality with 108,359 registered residents as of the Canada 2011 Census. The census metropolitan area of Thunder Bay located on Lake Superior has 121,596 inhabitants consisting of the Thunder Bay, the t… Thunder Bay City in Ontario, Canada is the most populated municipality with 108,359 registered residents as of the Canada 2011 Census. The census metropolitan area of Thunder Bay located on Lake Superior has 121,596 inhabitants consisting of the Thunder Bay, the townships of Conmee, Shuniah, O’Connor, and Gillies, the municipalities of Neebing and Oliver Paipoonge, and the Fort William First Nation.