The expedition, plagued by supply shortages due to conflicts between the NWC and HBC, was devastated by starvation on the return journey from the Arctic coast, leading to the deaths of the majority of the participants.
Ten years later, he and his family participated in James Sinclair's settler expedition to the Columbia District, part of a HBC plan to bolster the nascent Puget Sound Agricultural Company.
[1] Historical records indicate that Pierre St. Germain was married to a Métis woman named Lizette Sutherland, but no year of marriage is noted.
[1][2] St. Germain was regarded by HBC administrators as an intelligent and talented interpreter able to travel long distances without provisions, but was also seen as a renegade and an alcoholic.
"[1][2] Following the Napoleonic Wars, the Admiralty placed great emphasis on the discovery of a hypothetical Northwest Passage, supposedly offering a viable Arctic sea route between the Atlantic and Pacific Oceans.
[1][3][6] After traveling with the party to Fort Enterprise, he accompanied George Back and Robert Hood on a preliminary expedition to Point Lake on the Coppermine River.
St. Germain and the NWC's representative Willard Wentzel travelled to the nearby HBC post at Moose Deer Island, where the expedition's two hired Inuit interpreters, Tatannuaq and Hoeootoerock, had camped for the winter.
[7][8][6] The expedition started down the Coppermine in June 1821 and reached the sea on July 18, plagued by supply shortages exacerbated by the HBC-NWC rivalry.
Upon arriving at the shore, St. Germain, alongside fellow interpreter Jean Baptiste Adam, requested to leave the expedition, believing the next phase would be too hazardous.
[9] Unable to live off the land due to winter conditions, 11 out of the 20 members of the expedition died before they could be rescued by hunters under the leadership of Akaitcho.
[1] St. Germain returned to Fort Chipewyan on January 21, 1822. in early September of that year he was hired by Alexander McLeod as an interpreter at Lake Athabasca, at reduced wages due to cost-cutting measures by newly-appointed Rupert's Land governor George Simpson.
[12] In 1838, Simpson wrote in favor of a plan to settle residents of the Red River Colony in the region to counteract slowly growing numbers of American settlers.
Trader James Sinclair was appointed to lead the expedition, partially to remove his growing political influence in the colony, especially among fellow Métis settled in the area.
They crossed the Great Divide near the Goat Range and proceeded down the Kootenay, passing Lake Pend Oreille, and eventually reaching another HBC post at Fort Colvile.
[1] They acquired batteaux and sailed down the Columbia River, interrupted by a portage at Celilo Falls, towards the HBC stronghold of Fort Vancouver.
St. Germain and other Métis of French descent were considered ill-suited to agriculture and settled near Fort Cowlitz at a settlement named Saint Francis Xavier.