Southern Ontario in the context of "Tornado Alley"

Ottawa is the capital city of Canada. It is located in the southern portion of the province of Ontario, at the confluence of the Ottawa River and the Rideau River. Ottawa borders Gatineau, Quebec, and forms the core of the Ottawa–Gatineau census metropolitan area (CMA) and the National Capital Region (NCR). As of 2021, Ottawa had a city population of 1,017,449 and a metropolitan population of 1,488,307, making it the fourth-largest city and fourth-largest metropolitan area in Canada.

Ottawa is the political centre of Canada and the headquarters of the federal government. The city houses numerous foreign embassies, key buildings, organizations, and institutions of Canada's government; these include the Parliament of Canada, the Supreme Court, the residence of Canada's viceroy, and the Office of the Prime Minister.

The Province of Upper Canada (French: province du Haut-Canada) was a part of British Canada established in 1791 by the Kingdom of Great Britain, to govern the central third of the lands in British North America, formerly part of the Province of Quebec since 1763. Upper Canada included all of modern-day Southern Ontario and all those areas of Northern Ontario in the Pays d'en Haut which had formed part of New France, essentially the watersheds of the Ottawa River or Lakes Huron and Superior, excluding any lands within the watershed of Hudson Bay. The "upper" prefix in the name reflects its geographic position along the Great Lakes, mostly above the headwaters of the Saint Lawrence River, contrasted with Lower Canada (present-day Quebec) to the northeast.

Upper Canada was the primary destination of Loyalist refugees and settlers from the United States after the American Revolution, who often were granted land to settle in Upper Canada. Already populated by Indigenous peoples, land for settlement in Upper Canada was made by treaties between the new British government and the Indigenous peoples, exchanging land for one-time payments or annuities. The new province was characterized by its British way of life, including bicameral parliament and separate civil and criminal law, rather than mixed as in Lower Canada or elsewhere in the British Empire. The division was created to ensure the exercise of the same rights and privileges enjoyed by loyal subjects elsewhere in the North American colonies. In 1812, war broke out between Great Britain and the United States, leading to several battles in Upper Canada. The United States attempted to capture Upper Canada, but the war ended with the situation unchanged.

The Humber River (Ojibwe: Gabekanaang-ziibi, lit. 'river at the end of the trail') is a river in Southern Ontario, Canada. It is in the Great Lakes Basin, is a tributary of Lake Ontario and is one of two major rivers on either side of the city of Toronto, the other being the Don River to the east. It was designated a Canadian Heritage River on September 24, 1999.

The Humber collects from about 750 creeks and tributaries in a fan-shaped area north of Toronto that encompasses portions of Dufferin County, the Regional Municipality of Peel, Simcoe County, and the Regional Municipality of York. The main branch runs for about 100 kilometres (60 mi) from the Niagara Escarpment in the northwest, while another major branch, known as the East Humber River, starts at Lake St. George in the Oak Ridges Moraine near Aurora to the northeast. They join north of Toronto and then flow in a generally southeasterly direction into Lake Ontario at what was once the far western portions of the city. The river mouth is flanked by Sir Casimir Gzowski Park and Humber Bay Park East.

Oshawa is a city in Ontario, Canada, on the Lake Ontario shoreline. It lies in Southern Ontario, approximately 60 km (37 mi) east of downtown Toronto. It is commonly viewed as the eastern anchor of the Greater Toronto Area and of the Golden Horseshoe. It is the largest municipality in the Regional Municipality of Durham. The name Oshawa originates from the Ojibwa term aazhawe, meaning "the crossing place" or just "a cross".

Founded in 1876 as the McLaughlin Carriage Company by Robert McLaughlin, and then McLaughlin Motors Ltd by his son, Sam, General Motors of Canada's headquarters are located in the city. The automotive industry was the inspiration for Oshawa's previous mottos: "The City that Motovates Canada", and "The City in Motion". The lavish home of the automotive company's founder, Parkwood Estate, is a National Historic Site of Canada is located in the city.

The Golden Horseshoe (French: Fer à cheval doré) is a secondary region of Southern Ontario, Canada, which lies at the western end of Lake Ontario, with outer boundaries stretching south to Lake Erie and north to Lake Scugog, Lake Simcoe and Georgian Bay of Lake Huron. The region is the most densely populated and industrialized in Canada. Based on the 2021 census, with a population of 7,759,635 people in its core and 9,765,188 in its greater area, the Golden Horseshoe accounts for over 20 percent of the population of Canada and more than 54 percent of Ontario's population. The population of the greater area is estimated to have exceeded 11,000,000 people in 2024. The Golden Horseshoe is part of the Quebec City–Windsor Corridor, itself part of the Great Lakes megalopolis.

The core of the Golden Horseshoe starts from Niagara Falls at the eastern end of the Niagara Peninsula bordering the United States via New York and extends west, wrapping around the western end of Lake Ontario at Hamilton and then turning northeast to Toronto (on the northwestern shore of Lake Ontario), before finally terminating at Clarington in Durham Region. The term Greater Golden Horseshoe is used to describe a broader region that stretches inland from the core to the area of the Trent–Severn Waterway, such as Peterborough, in the northeast, to Barrie and Lake Simcoe in the north, and to the Grand River area, which includes cities such as Brantford and Guelph, to the west. The extended region's area covers approximately 33,500 km (13,000 sq mi), out of this, 7,300 km (2,800 sq mi) or approximately 22 percent of the area is covered by the environmentally protected Greenbelt. The Greater Golden Horseshoe forms the neck of the Ontario Peninsula.

St. Catharines is the most populous city in Canada's Niagara Region, the eighth largest urban area in the province of Ontario. As of 2021, St. Catharines has an area of 96.20 square kilometres (37.14 sq mi) and 136,803 residents. It lies in Southern Ontario, 51 kilometres (32 mi) south of Toronto across Lake Ontario, and is 19 kilometres (12 mi) inland from the international boundary with the United States along the Niagara River. It is the northern entrance of the Welland Canal. St. Catharines carries the official nickname "The Garden City" due to its 1,000 acres (4 km) of parks, gardens, and trails.

St. Catharines is between the Greater Toronto and Hamilton Area (GTHA) and the Canada–U.S. border at Fort Erie. Manufacturing was the city's dominant industry, as noted by the heraldic motto, "Industry and Liberality". General Motors of Canada, Ltd., the Canadian subsidiary of General Motors, was the city's largest employer, a distinction now held by the District School Board of Niagara. THK Rhythm Automotive, formerly TRW, operates a plant in the city, although in recent years, employment there has shifted from heavy industry and manufacturing to services.

Liriodendron tulipifera—known as the tulip tree, American tulip tree, tulipwood, tuliptree, tulip poplar, whitewood, fiddletree, lynn-tree, hickory-poplar, and yellow-poplar—is the North American representative of the two-species genus Liriodendron (the other member is Liriodendron chinense). It is native to eastern North America from Southern Ontario and possibly southern Quebec west to Illinois, and east to southwestern Massachusetts, then south to central Florida and Louisiana.

The tulip tree is the tallest tree of the Nearctic temperate deciduous forest. It can grow to more than 50 m (160 ft) in virgin cove forests of the Appalachian Mountains, often with no limbs until it reaches 25–30 m (80–100 ft) in height, making it a very valuable timber tree.