Ontario came into being as a province of Canada in 1867. This article also covers the pre-1867 history of the territory Ontario now occupies.

For a complete list of the premiers of Ontario, see List of Ontario premiers.

1762 and earlier

• Before the arrival of Europeans, the territory which is now Ontario was occupied mainly by Algonquian and Iroquoian first nations.
• 1610 to 1612– exploration of what is now southern Ontario by Étienne Brûlé
• 1611–Henry Hudson visits Hudson Bay and claims the region for Great Britain.
• 1615–Samuel de Champlain visits Lake Huron, after which French missionaries establish outposts in the region.
• 1648–Iroquois destroy a Jesuit mission near the site of present-day Midland (see Canadian Martyrs)
• circa 1650–Iroquois drive the Hurons from their territory in what is now southern Ontario
• 1670–The Hudson's Bay Company is granted a British royal charter to conduct the Indian Trade in the territory whose rivers drain into Hudson Bay; this area includes much of what is now Northern Ontario
• 1673–establishment of Fort Frontenac near the site of present-day Kingston
• 1730–The Hudson's Bay Company establishes a trading post at Moose Factory, now the oldest English-speaking settlement in Ontario. Over the years Hudson's Bay traders and their Métis descendants establish and maintain several settlements in the western Great Lakes, notably two which develop into Sault Ste. Marie and Detroit.

Province of Quebec, 1763 to 1790

• 1763–Great Britain acquires Canada through the Treaty of Paris and renames it Quebec in the British Royal Proclamation of 1763.

• Quebec Act of 1774 was enacted to assure the loyalty of the newly acquired Quebec, through assuring the existence of the Catholic faith, and the renactment of French civil law. The boundaries of Quebec were expanded to include the Ohio Country and Illinois Country, from the Appalachian Mountains on the east, south to the Ohio River, west to the Mississippi River and north to the southern boundary of lands owned by the Hudson's Bay Company, or Rupert's Land.

• 1784–About 10,000 United Empire Loyalists are settled in what is now southern Ontario, chiefly in Niagara, around the Bay of Quinte, and along the St. Lawrence River between Lake Ontario and Montreal. They are soon followed by many more Americans attracted by cheap land.

At the same time large numbers of Iroquois loyal to Britain arrive from the United States and are settled on reserves west of Lake Ontario.

Kingston and Hamilton became important settlements as a result of the influx of Loyalists.

• 1788–The British purchase 250,000 acres (1,000 km&sup2) on which they begin the settlement of York, now Toronto

Upper Canada, 1791 to 1840

• 1791–The Constitutional Act of 1791 divides Quebec into Upper Canada (the part of present-day Ontario south of Lake Nipissing plus the current Ontario shoreline of Georgian Bay and Lake Superior) and Lower Canada (the southern part of present-day Quebec). Upper Canada's first capital is Newark (present-day Niagara-on-the-Lake); in 1796 it is moved to York, now Toronto.

The population of Upper Canada is about 14,000 (Lower Canada's is about 165,000).

• 1793–John Graves Simcoe is appointed as the first governor of Upper Canada. He encourages immigration from the United States, builds roads, and abolishes slavery, which was not an important economic institution in Upper Canada. Slavery is abolished in 1793 by the Act Against Slavery, with the intent that all slaves be released by 1810; this goal was probably reached ahead of time.
• 1794–The Jay Treaty is signed November 19 by which Britain agreed to vacate its Great Lakes forts on U.S. territory.
• 1800–First European settlement on the site of present-day Ottawa
• 1803–The Northwest Company moves its mid-continent headquarters from Grand Portage, Minnesota to Fort William, now part of Thunder Bay to be in Upper Canada.
• 1803–Thomas Talbot retires to his land grant in Western Ontario and begins settling it. He eventually becomes responsible for settling 65,000 acres (260 km&sup2). His insistence on the provision and maintenance of good roads, and on reserving land along main roads to productive uses rather than to clergy reserves leads to this region becoming the most prosperous in the province.
• 1804–First European settlement on the site of present-day Waterloo
• 1807–First settlement, Ebytown, on the site of present-day Kitchener
• 1812–1814–The War of 1812 with the United States. Upper Canada is the chief target of the Americans, since it is weakly defended and populated largely by American immigrants. However, division in the United States over the war, the incompetence of American military commanders, and swift and decisive action by the British commander, Sir Isaac Brock, keep Upper Canada British.

One of the legacies of the war in Upper Canada is strong feelings of anti-Americanism which persist to this day and form an important component of Canadian nationalism.

• 1816–Waterloo adopts its current name to honour the battle of Waterloo.
• 1817–By the Rush-Bagot Convention Britain and the United States agree to keep large war vessels out of the Great Lakes.
• 1818–The Convention of 1818 reduces boundary and fishing disputes between British North America and the United States.
• 1821–The Northwest Company merged with the Hudson's Bay Company.
• 1824–The Church of Scotland is granted a share of the revenues from clergy reserves.
• 1826–first settlement of London
• 1833–Building of the first Welland Canal by William Merritt
• 1837–Rebellions of 1837 - Upper Canada Rebellion in favour of responsible government; a similar rebellion (the Patriotes Rebellion) occurred in Quebec.
• 1839–Lord Durham publishes his report on the causes of the rebellions in 1837.
• 1840–The assembly passes a law providing for the sale of the clergy reserves, but it is disallowed by the British government.
• 1840–Upper Canada is now heavily in debt as a result of its heavy investments in canals.

The united Province of Canada, 1841 to 1866

• 1841–Upper and Lower Canada are united by the Act of Union (1840) to form the Province of Canada, as recommended by Durham. Upper Canada becomes known as Canada West and Lower Canada as Canada East.
• 1841–Sydenham dies in a riding accident and is replaced by Sir Charles Bagot. The movement for responsible government which had been growing under Sydenham is now so strong that Bagot realizes that to govern effectively he must admit French leaders to his executive council. Once admitted, Canada East Reformer Louis-Hippolyte Lafontaine insists that Canada West Reformer Robert Baldwin also be admitted. Bagot admits Baldwin as well, creating a Reform bloc.
• 1843–Bagot retires because of illness and is replaced by Sir Charles Metcalfe, who is determined to make no further concessions to the colonists. Metcalfe refuses a demand by Baldwin and Francis Hincks that the assembly approve official appointments. The ministry in the assembly resigns, and in the ensuing election a slim majority supporting Metcalfe is returned.
• 1846–The Colonial Secretary, Lord Grey, rules that the British North American lieutenant governors must rule with the consent of the governed. Executive councils are to be selected from the majority in the assembly, and change when the confidence of the assembly changes. Britain is abandoning the mercantilist principles which have guided its imperial policy, and since colonial trade will no longer be restricted, local colonial politics need no longer be restricted.
• 1848–Lord Elgin, who had replaced Metcalfe in 1847, asks Baldwin and Lafontaine to form a government following their success in elections for the assembly. This is the Province of Canada's first responsible government.
• 1849–Elgin signs the Rebellion Losses Bill, which provided compensation for losses suffered during the Patriotes Rebellion, over the opposition of English conservatives (Tories) in Canada East, who were accustomed to having the governor support them. A Tory mob burns down the parliament building in Montreal but Elgin, supported by majorities in both Canada East and Canada West (which had already passed a similar bill), does not back down, and responsible government is established in fact.
• 1849–The Canada East Tories then sponsor an Annexation Manifesto calling for the province of Canada to join the United States. They were motivated by the loss of trade threatened by the repeal of the British Corn Laws. However, the rest of the Canadian population opposes the manifesto, including the Tories of Canada West, who favour provincial union. Union with the United States ceases to be an important political issue.
• 1850–The Robinson Treaties are negotiated by William Benjamin Robinson with the Ojibwe nation transferring to the Crown the eastern and northern shores of Lake Huron and the northern shore of Lake Superior.
• 1851 - The population of Canada West is now numerically superior to that of Canada East. Politicians of Canada West begin to argue for representation by population.
• 1854–An agreement for reciprocal lowering of trade barriers is reached between British North America and the United States. The British North American provinces can now send their natural products (principally grain, timber, and fish) to the United States without tariff, while American fishermen are allowed into British North American fisheries. Lake Michigan and the St. Lawrence River are opened to ships of all signatories.
• 1854–A law secularizing the clergy reserves is passed; the Anglican and Presbyterian churches retain their endowments.
• 1855–The American canal at Sault Ste. Marie on the St. Marys River (Michigan-Ontario) opened in May which opened Lake Superior to American and Canadian navigation, and made access to the Red River colony easier.
• 1858–Canada has become increasingly sectional, with Canada West electing Clear Grit Liberals and Canada East electing Conservatives. A coalition government led by John A. Macdonald and Antoine-Aimé Dorion falls in two days. In the assembly Alexander Galt proposes a federal union of the British North American colonies as a solution to the problem.
• 1858– The provisional judicial districts of Algoma and Nipissing are created, the first in Northern Ontario.
• 1859–The Clear Grit Liberals under George Brown propose specific arrangements for a federal union of the two Canadas.
• 1864–A committee proposed by George Brown to inquire into solutions to the parliamentary deadlock between the Canadas recommends a federal union of the British North American colonies, a solution which is welcomed by all sides. A government of Liberals and Conservatives, the Great Coalition , is formed to pursue this goal. Representatives of the coalition attend the Charlottetown Conference called to discuss union of the maritime colonies and persuade the representatives to endorse the Canadian plan for a broader federal union. A conference in Quebec City draws up the Quebec Resolutions, a plan for this union.
• 1866–The Westminster Conference endorses the Quebec Resolutions with minor changes.

Canada, Dominion of the British Empire, 1867 to 1930

Dominion of Canada 1867-1982. The Province of Ontario 1867 and after.

• 1867–The parliament of the United Kingdom passes the British North America Act, by which the Province of Canada, New Brunswick, and Nova Scotia join to form the country of Canada. Upper Canada becomes the province of Ontario, with its capital at Toronto. Canada remained self-governing locally, but the British continued to control its external affairs.
• 1870–Orange Ontario largely supports the trying of Louis Riel for treason for executing Thomas Scott during the so-called Red River Rebellion, while Quebec supports Riel. Although Riel's government was finally recognized by Canada, its actions are destined to be described as a rebellion ever after. The split between Ontario and Quebec aggravates tensions between Quebec and English Canada and between English and French.
• 1870–the head of construction for the Dawson Road to Manitoba is named Prince Arthur's Landing by Colonel Garnet Wolseley during the Red River Rebellion.
• 1870s–The growth of industry in Ontario and Quebec leads to a movement for protective tariffs.
• 1871–Thunder Bay District, Ontario is created out of the western portion of Algoma District, Ontario but its northern and western boundaries remain in dispute.
• 1872–contracts are let by the federal government to survey the route through Northwestern Ontario of the Canadian Pacific Railway, to stimulate settlement of Western Canada, to bring Western agricultural and other products to Ontario and Quebec, and to link British Columbia to the rest of the country. The railway is part of Sir John A. Macdonald's National Policy.
• 1872–1896–The provincial government of Oliver Mowat vigorously defends provincial rights and expands the scope of provincial power.
• 1874–First issue of The Nation, founded by members of the Canada First movement to help in creating a Canadian nationality. Although the journal only lasted until 1876, other publications continued the effort after it stopped publishing.
• 1875–Construction of the Canadian Pacific Railway begins in June at Fort William, Ontario.
• 1879–The federal government of Sir John A. Macdonald, as part of its national Policy, institutes protective tariffs on manufactures and on farm products; the tariffs help Ontario industry but hurt farmers.
• 1882–The Canadian Pacific Railway Thunder Bay to Winnipeg is completed in June by the federal government.
• 1883–Important mineral deposits are found near Sudbury; this and similar discoveries, especially near Cobalt, triggered a mining boom in Northern Ontario. The region acquires a large French-speaking population as Quebeckers move there to work in the boom.
• 1885–The split between Orange Ontario and Roman Catholic Quebec is aggravated further by Ontario's vigorous support for the hanging of Louis Riel, convicted of treason for his role in the North-West Rebellion that year.
• 1885–Rainy River District, Ontario is created after Ontario wins its boundaries case before the Judicial Committee of the Privy Council.
• 1889–The Imperial Parliament confirms Ontario's right to Northwestern Ontario west to Lake of the Woods and north of the Albany River by incorporation of sections of the District of Keewatin.
• 1890–1896–Tension between English and French is further aggravated by the disagreement between Ontario and Quebec over the Manitoba Schools Question. Ontario objects to a federal remedial bill to restore French schools in Manitoba in part because of its support for provincial rights, and in part because of the influence of a Protestant Equal rights movement begun in response to pro-Roman Catholic policies instituted in Quebec.
• 1896–The Judicial Committee of the Privy Council rules that the federal government may exercise its reserve power only in time of war. This results in an increase in provincial power as areas of provincial responsibility are interpreted more broadly to accommodate new types of government initiative (social welfare, for example).
• 1896–Sir Oliver Mowat resigns after 24 years as premier.
• 1906–Establishment of the Hydro-Electric Power Commission of Ontario by the government of Sir James P. Whitney at the urging of Sir Adam Beck.
• 1912–Ontario acquires its current territory by incorporation of further sections of the North-West territories
• 1912–Regulation 17 bans teaching in French after the first year of school and the teaching of French after the fourth; this infuriates Quebeckers and further divides the country.
• 1916–The city of Berlin, under pressure to demonstrate the loyalty of its citizens of German origin to the war effort changes its name to Kitchener, in honour of Lord Kitchener
• 1916–1927–Ontario prohibits the domestic consumption of beer and spirits. Beer and spirits continue to be produced for export, however, largely for illegal sale in the United States. To make repeal acceptable, drinking in Ontario is encumbered by extensive regulations which lasted till the 1970s and made Ontario the laughingstock of Canada.

Canada, Sovereign Dominion, 1931 to 1982

• 1931 - The Statute of Westminster removes the legislating power of the United Kingdom over the Dominion of Canada, but does not settle the question of an amending formula for the British North America Act.
• 1937–Premier Mitchell Hepburn uses the Ontario Provincial Police to suppress an CIO strike at General Motors in Oshawa after the federal government refuses to suppress it. Hepburn is unsuccessful in keeping the CIO out of Ontario.
• 1943–George Drew and the Progressive Conservative Party of Ontario are elected, beginning 42 years of Conservative government.
• 1951–In response to a civil rights movement which originated in opposition to racial discrimination in Dresden, Ontario , the government of Leslie Frost passes Canada’s first Fair Employment Practices Act , which forbids discrimination on the basis of race, creed, colour, nationality, ancestry or place of origin. However, the act is enforced administratively, with prosecution only a last resort.
• 1951–The Frost government passes Ontario’s first equal pay legislation, the Female Employees Fair Remuneration Act .
• 1954–The Frost government introduces Canada’s first Fair Accommodation Practices Act . Like the Fair Employment Practices Act it is enforced administratively, with prosecution only a last resort.
• 1955–The first conviction under the Fair Accommodation Practices Act, of Kay's Cafe in Dresden, the site of the original complaint of racial discrimination in Dresden, is overturned on appeal.
• 1956–First successful prosecution under the Fair Accommodation Practices Act, again of Kay's Cafe in Dresden
• 1962–Passage of the Ontario Human Rights Code , which amalgamates and extends previous laws about civil rights.
• 1966–The government of John Robarts introduces publicly funded medicine.

Independent Canada, 1982 and after

• 1982– Canada Act 1982, an Act of Parliament passed by the British Parliament that severed remaining constitutional and legislative ties between the United Kingdom and Canada.
• 1985–The Progressive Conservative government of Frank Miller falls, ending 42 years of the "Big Blue Machine" and introducing a period of political instability.
• 1993–The government of Bob Rae introduces its so-called social contract which re-opens public-sector collective agreements with the intent of rolling back wages; his New Democratic Party's traditional labour support is greatly weakened.
• 1998–The government of Mike Harris begins privatizing the Hydro-Electric Power Commission of Ontario.
• 2000–Seven people die after contamination of Walkerton's water supply.
• 2003–Serious outbreak of SARS in Toronto.
• 2003–Two decisions of the Ontario Court of Appeal legalize same-sex marriage in Ontario.