The Coteau-du-Lac National Historic Site is located 40 km southwest of Montréal on the shores of the St. Lawrence River, and offers a window on a particularly rich history going back several millennia in time.

Owing to its strategic position on the River, the main route into inland North America, this site has played a major role in the development of river transportation in Canada. At first a portage for nomadic Aboriginal peoples, Coteau-du-Lac later became a genuine bypass for travellers from Great Britain and France.

By the late 18th century, a lock canal is constructed on this location. It was the first work of its kind in North America and was to serve as a forerunner of the modern-day St. Lawrence Seaway.