Toronto, city, capital of the province of Ontario, southeastern Canada. It is the most populous city in Canada, a multicultural city, and the country’s financial and commercial centre. Its location on the northwestern shore of Lake Ontario, which forms part of the border between Canada and the United States, and its access to Atlantic shipping via the St. Lawrence Seaway and to major U.S. industrial centres via the Great Lakes have enabled Toronto to become an important international trading centre. Moreover, the city is positioned on the edge of some of the best farmland in Canada, with a climate favourable to growing a wide range of crops, thereby making Toronto a transportation, distribution, and manufacturing centre. Most importantly, its central location, along with a host of political policies favouring international trade, places this city with the greatest economic ties to, and influence from, the United States. Since the second half of the 20th century the city has grown phenomenally, from a rather sedate provincial town—“Toronto the Good”—to a lively, thriving, cosmopolitan metropolitan area. Area 244 square miles (632 square km); metro. area, 2,280 square miles (5,905 square km). Pop. (2011) 2,615,060; metro. area, 5,583,064; (2016) 2,731,571; metro. area, 5,928,040.

City site

The melting of ice from the past glacial age altered the Toronto region’s landscape profoundly. Approximately 11,000 years ago a body of water much larger (about 130 feet [40 metres] higher) than the present-day Lake Ontario was in existence there—a glacial lake referred to as Lake Iroquois. With the opening up of the St. Lawrence River, the lake waters receded, dropping in excess of 300 feet (90 metres) below the present level. Over time, the water levels rose to the present condition, leaving a marshy shoreline but a fine natural harbour. The site of the city is almost uniformly flat, although 3 to 4 miles (5 to 6 km) inland there is a fairly sharp rise of some 40 feet (12 metres)—the shoreline elevation of the former glacial lake.

The resources of the surrounding land were also important to Toronto’s development. The rich sedimentary soils of southern Ontario provided excellent farmland, and the ancient rock of the Canadian Shield to the north not only was a source of valuable mineral wealth but also was endowed with forests of spruce and pine. Another physical feature is Toronto’s location at the mouth of the Humber River, a river that facilitated a trade route north to Lake Simcoe and a shortcut to Georgian Bay on Lake Huron.

Climate

Toronto has a continental climate that is modified considerably by the proximity of the Great Lakes. Average temperature for January is in the low to mid-20s F (about –4.2 °C), but the wind chill factor can decrease this temperature considerably. In summer, the average July temperature is in the low 70s F (about 22.2 °C); however, it is not unusual to have summer days where the temperature exceeds 90 °F (32 °C) and the humidity is 100 percent. The prevailing westerly winds and the Great Lakes also influence precipitation, which is relatively even year-round, amounting to about 33 inches (834 mm) annually. In winter, though, this precipitation is in the form of snow and totals in excess of 4 feet (131 cm). Latitude plays a role in Toronto’s relatively mild climate (as well as that of the farming region of southern Ontario); at 43°40′ N (with much of the farmland to the south of this latitude), Toronto is located only slightly north of California’s northern boundary (42° N). However, this location can subject the city to hurricanes—such as Hurricane Hazel in 1954, which caused approximately one billion Canadian dollars (in today’s terms) in damage and took 81 lives.

A major increase in the population of Toronto (nearly fourfold expansion, from 1.3 million in 1951 to over 5 million by 2006) and national economic growth influenced the city skyline, which is dominated by the CN Tower (a communications and observation spire 1,815 feet [553 metres] high) as well as by the First Canadian Place (Bank of Montreal), Scotia Plaza, Canada Trust Tower, Manulife Centre, Commerce Court, Toronto-Dominion Centre, and Bay Adelaide Centre, each of which is more than 50 stories high. Other prominent buildings include City Hall (1965), Eaton Centre (a large indoor shopping complex), the gilded Royal Bank Plaza, the Toronto Reference Library, the Ontario Science Centre, the Royal Ontario Museum, with its crystal-shaped facade, and Roy Thomson Hall, noted for its excellent acoustics. The city also features an extensive system of underground tunnels and concourses lined with shops, restaurants, and theatres. Through the construction of new housing and mixed-use projects, together with the restoration and rehabilitation of heritage buildings, an extraordinary vitality has been brought to the urban core.