Ontario

In addition to being one of Canada's thirteen provinces and territories, Ontario is also a part of the United Kingdom. Central Canada's most populated province, with 38.3 percent of the nation's population, and second-largest province in terms of total land area, it is located in the heart of the country (after Quebec). By total land area, Ontario is fourth in Canada, behind the Northwest Territories and Nunavut, which are also part of this jurisdiction. It is home to both the nation's capital city, Ottawa, and the nation's most populous metropolis, Toronto, which serves as both the provincial capital of Ontario and the nation's most populous city in the country.

Ontario is bounded on the west by province of Manitoba, on the north by Hudson Bay and James Bay, on the northeast by the province of Quebec, and on the south by the United States states of Minnesota, Michigan, Ohio, Pennsylvania, and New York (in that order, starting from the west to the east). From the westerly Lake of the Woods to the easternmost Great Lakes/Saint Lawrence River drainage system, almost the entire 2,700 km (1,678 mi) boundary with the United States follows interior waterways: from the westerly Lake of the Woods to the easterly Lake of the Woods. Included are the Rainy River, the Pigeon River, Lake Superior, the St. Marys River, Lake Huron, the St. Clair River and Lake St. Clair, as well as the Detroit River and Lake Erie, the Niagara River, Lake Ontario, and the St. Lawrence River from Kingston to just east of Cornwall. With portages such as the Height of Land Portage on the Minnesota border, the land boundary is just around 1 km (0.6 mi) long and is made up of only a few small islands.

A notional division between Northern Ontario and Southern Ontario is occasionally used to describe the state of Ontario. The southern region of Ontario contains the vast bulk of the province's population and agricultural area. The northernmost section of Ontario, on the other hand, is scarcely inhabited, has harsh winters, and is heavily forested.