Ontario is one of the provinces of Canada, located in east-central Canada. It is Canada’s most populous province or territory and fourth largest in total area. It is home to the nation’s capital city, Ottawa, and the nation’s most populous city, Toronto.

Ontario is bordered by the province of Manitoba to the west, Hudson Bay and Quebec to the north, and to the south by the U.S. states of Minnesota, Michigan, New York, Ohio and Pennsylvania. All but a small part of Ontario’s 2,700 km (1,677 mi) border with the United States follows inland waterways: from the west at Lake of the Woods, eastward along the major rivers and lakes of the Great Lakes/St. Lawrence River drainage system. These are the Rainy River, the Pigeon River, Lake Superior, the St. Mary’s River, Lake Huron, the St. Clair River, Lake St. Clair, the Detroit River, Lake Erie, the Niagara River, Lake Ontario and along the St. Lawrence River from Kingston, Ontario to the Quebec boundary just east of Cornwall, Ontario.