Thunder Bay is a city in and the seat of Thunder Bay District, Ontario, Canada. It is the most populous municipality in North-western Ontario and the second most populous municipality in Northern Ontario. The census metropolitan area of Thunder Bay 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.
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 grew into an important transportation hub with its port forming an important link in the shipping of grain and other products from western Canada, through the Great Lakes and the Saint Lawrence Seaway, to the east coast. Forestry and manufacturing played important roles in the city's economy. They have declined in recent years, but have been replaced by a "knowledge economy" based on medical research and education.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 takes its name from the immense Thunder Bay at the head of Lake Superior, known on 18th-century French maps as Baie du Tonnerre (Bay of Thunder). The city is often referred to as the "Lakehead", or "Canadian Lakehead", because of its location at the end of Great Lakes navigation on the Canadian side of the border.
As the largest city in North-western Ontario, Thunder Bay is the region's commercial, administrative and medical centre. Many of the city's largest single employers are in the public sector. The City of Thunder Bay, the Thunder Bay Regional Health Sciences Centre, the Lakehead District School Board and the Government of Ontario each employ over 1,500 people. Resolute Forest Products is the largest private employer, employing over 1,500 people.
Bombardier Transportation operates a 553,000 square feet plant in Thunder Bay which manufactures mass transit vehicles and equipment. The plant was built by Canadian Car and Foundry to build railway box cars in 1912, and began building passenger railcar and transit cars from 1963 onwards.
Among the main sectors are: Management, Business, Finance and Administration, Natural and Applied Sciences, Health, Education, Law, and Government, Art, Culture, Recreation, and Sport, Sales and Services, Trades, Transport and Equipment Operators, Natural Resources and Agriculture, Manufacturing and Utilities.
Thunder Bay remains an important part of the Saint Lawrence Seaway. In an effort to rejuvenate its economy, the city has been actively working to attract quaternary or "knowledge-based" industries, primarily in the fields of molecular medicine and genomics. The city is home to the western campus of the Northern Ontario School of Medicine, the first medical school to open in Canada in a generation. The city also has a law school.
Thunder Bay has a population of over 107,909 people. Thunder Bay also forms part of the wider Thunder Bay metropolitan area which has a population of over 121,621 people.