Thunder Bay is a city in, and the seat of, Thunder Bay District, Ontario, Canada. It is the most populous municipality in Northwestern Ontario with a population of 108,359 as of the Canada 2011 Census, and the second most populous in Northern Ontario after Greater Sudbury. The census metropolitan area of Thunder Bay has a population of 121,596, and consists of the city of Thunder Bay, the municipalities of Oliver Paipoonge and Neebing, the townships of Shuniah, Conmee, O'Connor, and Gillies, and the Fort William First Nation.