The Kaministikwia Route
This chain of rivers, lakes and portages linking the St. Lawrence system with the waterways of the prairies had been known to the Indians for centuries when Jacques de Noyon first travelled it in 1688. After 1800, when the boundary settlement had placed the more southerly Grand Portage in the United States, the North West Company re-opened Kaministikwia route, which for almost 25 years was the main highway to the west. From Fort William at the mouth of the river canoes were tracked upriver to this point, the first major obstacle on the route.
Plaque via Alan L. Brown's site Ontario Plaques. Full page here.