Mississauga (mĭsĭsawˈgə) [key], city (1991 pop. 463,388), S Ont., Canada, 12 mi (20 km) W of Toronto on Lake Ontario. A residential suburb of Toronto and a growing transportation and industrial center, it is one of Canada's fastest-growing cities. Its manufactures include aircraft, motor vehicles, engines, chemicals, petroleum, steel and rubber products, cement, appliances, and printed materials. It has a port and is the site of Toronto International Airport. Originally an agricultural and then residential area, it had a population of 15,000 in 1945.