Lake Ontario, the smallest of the Great Lakes, was discovered by Samuel de Champlain and Etienne Brule in 1615. On early maps it appeared various as Lac St. Louis or Lake Frontenac, but the name Ontario was settled after around 1733. It means "high rocks near the water."
The lake was the scene of naval engagements during the French and Indian Wars and again in 1813. It was always a major trade route, as early as the fur trade, and became part of the St. Lawrence Seaway, a joint project of Canada and the United States. Canada`s largest city, Toronto, is located on its north shore.
The first sailing ships on the Great Lakes were four built on Lake Ontario by LaSalle in 1678 or earlier, to provide transportation between Fort Frontenac and his post at the mouth of the Niagara.