Grand Portage was a fur-trade depot and route of the voyageurs at the western extremity of Lake Superior. It was the first and most strenuous of the 29 portages from Lake Superior west to Lac La Croix, requiring that each voyageur carry 4 loads of 80 kg over some 14 km of rocky trails around the cascades of the Pigeon River. The Pigeon River route had long been used by native people and was opened to the fur trade by Pierre Gaultier de Varennes et de La Vérendrye.
The North West Co (NWC) established an extensive post at the mouth of the river, which by 1784 was the wilderness capital of the fur trade, providing a meeting place for the voyageurs bringing supplies from Montréal (porkeaters) and the traders bringing furs from the North West (winterers, see Wintering Partner). Within the post, which was protected by a 5-m high palisade, reinforced with a bastion and a heavy gate, were the Great Hall, living quarters, shops, warehouses and a stone powder magazine. Because the settling of the Canada-US boundary left the post in American territory, the post was abandoned in late 1802 and NWC activities were relocated the following year at Fort William at the mouth of the Kaministiquia River. This route, which had been travelled by Jacques de Noyon in 1688, was more arduous than Grand Portage, requiring a portage of Kakabeka Falls and a gruelling haul over the height of land to the Savanne River.