Toronto (/tɵˈrɒntoʊ/, colloquially /ˈtrɒnoʊ/) is the largest city in Canada and the provincial capital of Ontario. It is located in Southern Ontario on the northwestern shore of Lake Ontario. A relatively modern city, Toronto's history dates back to the late-18th century, when its land was first purchased by the British monarchy from the Mississaugas of the New Credit. The settlement was later established as the Town of York and proclaimed as the new capital of Upper Canada by its lieutenant-governor, John Graves Simcoe. In 1834, York was incorporated as a city and renamed to its present name. The city was ransacked in the Battle of York during the War of 1812 and damaged in two great fires in 1849 and in 1904. Since its incorporation, Toronto has repeatedly expanded its borders through amalgamation with surrounding municipalities, most recently in 1998.

With over 2.6 million residents, it is the fifth most populous city in North America. Its metropolitan area has over 5.5 million residents. Toronto is at the heart of the Greater Toronto Area (GTA), and the densely populated region in Southern Ontario known as the Golden Horseshoe, which has a population of nearly 9 million people as of 2011.[2][3][4] The census metropolitan area (CMA) had a population of 5,583,064,[5] and the Greater Toronto Area had a population of 6,054,191 in the 2011 Census.[6] Its cosmopolitan and international population[7] reflects its role as an important destination for immigrants to Canada.[8] Toronto is one of the world's most diverse cities by percentage of non-native-born residents, with about 49% of the population born outside Canada.[7][8][9] Toronto is also consistently rated as one of the world's most livable cities by the Economist Intelligence Unit and the Mercer Quality of Living Survey.[10][11]

As Canada's commercial capital and one of the world's top financial centres, Toronto is considered an alpha world city by the Globalization and World Cities (GaWC) study group.[12][13] It is home to the Toronto Stock Exchange, the world's seventh largest in terms of market value. Toronto contains more corporate headquarters than any other Canadian city, including those of Canada's five largest banks.[14] Toronto's leading economic sectors include finance, business services, telecommunications, aerospace, transportation, media, arts, film, music, television production, publishing, software production, medical research, education, tourism, engineering, and sports industries.[15][16] According to Forbes, Toronto is the tenth-most economically powerful city in the world and one of the fastest growing among the G7 nations, whilst PwC ranks the city as the world's second-best "metro powerhouse".[17][18] Toronto was ranked twelfth in the world and fourth in the Americas in 2010 for economic innovation by 2thinknow.[19] The cost of living in Toronto was ranked highest in Canada in 2011.