The St. Lawrence River is located in Canada and the United States. It originated in Lake Ontario, from Kingston at the mouth of Lake Ontario to Cornwall in Ontario (Cornwall), which is the boundary between the United States and Canada. Cornwall and below are all in Canada. In the west of Montreal, it converges with the Ottawa River, passes through the city of Three Rivers, and suddenly opens up to Quebec City, and finally enters the sea at the Gabor Strait, with a total length of 3260 kilometers. St. Lawrence has abundant water and low sediment content. Its tributaries include the Ottawa River, the Rivière Richelieu and the Rivière Saguenay, and Lake Champlain in Vermont is also a branch of its water system. The St. Lawrence water system and the Great Lakes constitute the world's largest freshwater water system. It is the gateway from the Great Lakes system to the Atlantic Ocean and has an important position. 80% of Quebec’s population and almost all industries are concentrated on both sides of the river.