First Nations fishing camps were established around the waterways of Toronto as early as 1,000 BCE. By 500 CE, up to 500 people lived along each of the three major rivers of Toronto (Don, Humber, and Rouge River). Early on, First Nations communities had developed trails and water routes in the Toronto area. These led from northern and western Canada to the Gulf of Mexico. One trail, known as the "Toronto Passage", followed the Humber River northward as an important overland shortcut between Lake Ontario and the upper Great Lakes.