Thunder Bay

Northwestern Ontario is a region in the Canadian province of Ontario that lies north and west of Lake Superior and west of Hudson Bay and James Bay. Its western boundary is Manitoba, but its right to the region was confirmed by the Judicial Committee of the Privy Council in 1884 and the Canada (Ontario Boundary) Act, 1889. The region includes the districts of Kenora, Rainy River, and Thunder Bay, which are home to several dozen First Nations communities. The major communities in Northwestern Ontario are Thunder Bay, Kenora, Dryden, Fort Frances, Sioux Lookout, Greenstone, Red Lake, Marathon, and Atikokan.

Thunder Bay is the most populous municipality in Northwestern Ontario, with a population of 108,843 according to the 2021 Canadian Census. It is located on Lake Superior and is the second most populous municipality in Northern Ontario after Greater Sudbury. The census metropolitan area of Thunder Bay includes the city, the municipalities of Oliver Paipoonge and Neebing, the townships of Shuniah, Conmee, O'Connor, and Gillies, and the Fort William First Nation.

European settlement in the region began in the late 17th century with a French fur trading outpost on the banks of the Kaministiquia River. It became an important transportation hub with its port serving as a link for shipping grain and other products from western Canada through the Great Lakes and the Saint Lawrence Seaway to the east coast. Although forestry and manufacturing played significant roles in the city's economy, they have declined in recent years and been replaced by a "knowledge economy" based on medical research and education. Thunder Bay is the site of the Thunder Bay Regional Health Research Institute.

The City of Thunder Bay was formed on January 1, 1970, through the merger of the cities of Fort William, Port Arthur, and the geographic townships of Neebing and McIntyre. The city is named after the immense Thunder Bay at the head of Lake Superior, known on 18th-century French maps as Baie du Tonnerre (Bay of Thunder). It is often referred to as the "Lakehead" or "Canadian Lakehead" due to its location at the end of Great Lakes navigation on the Canadian side of the border.