Ontario is the southernmost province of Canada. Located in Central Canada, Ontario is the country’s most populous province. As of the 2021 Canadian census it is home to over 14 million people, which is approximately 38.5% of the country’s population. Ontario is the second-largest province by total area, after Quebec, and the fourth-largest jurisdiction of all the Canadian provinces and territories. It is home to the nation’s capital, Ottawa, and its most populous city,^[which is Ontario’s provincial capital.

Ontario is bordered by the province of Manitoba to the west, Hudson Bay and James Bay to the north, and Quebec to the east and northeast. To the south, it is bordered by the U.S. state (from west to east) Minnesota, Michigan, Ohio, Pennsylvania (through Lake Erie), and New York. Almost all of Ontario’s 2,700-kilometre (1,700 mi) border with the United States follows rivers and lakes: from the westerly Lake of the Woods, eastward along the major rivers and lakes of the Great Lakes drainage system. There is only about one kilometre (0.62 mi) of actual land border, made up of portages including Height of Land Portage on the Minnesota border.

The great majority of Ontario’s population and arable land are in Southern Ontario, and while agriculture remains a significant industry, the region’s economy depends highly on manufacturing. In contrast, Norther Ontario is sparsely populated with cold winters and heavy forestation,with mining and forestry making up the region’s major industries.