Sir Alexander Mackenzie (Alasdair MacCoinnich) lived from 1764 to 12 March 1820. He was an explorer of western Canada. The wider picture in Scotland at the time is set out in our Historical Timeline.
Alexander Mackenzie was born in Stornoway on the Isle of Lewis in the Western Isles. In 1774 his family emigrated to New York, and then moved north to Montreal in 1776 during the American Revolution. In 1779 Alexander joined the North West Company, a fur trading business with its headquarters in Montreal that operated in competition with the Hudson's Bay Company.
In 1788 he travelled to Lake Athabasca and founded Fort Chipewyan. While there he heard that the First Nations people knew of rivers that flowed to the north west. Mackenzie set out by canoe to see for himself and on 10 July 1789 found what has since been called the Mackenzie River. Mackenzie hoped that it flowed into the Pacific at Cook Inlet in southern Alaska and followed it to its mouth. On discovering that the river flowed into the Arctic Ocean rather than the Pacific, Mackenzie named it "Disappointment River".
After visiting Britain in 1791 to study new ways of measuring longitude, Mackenzie was back in Canada in 1792, still looking for a route through to the Pacific Ocean. This time he and his native guides worked their way along the Peace River and crossed the great divide to the upper reaches of the Fraser River. On being advised that the lower reaches of the Fraser were unnavigable and populated by hostile natives, Fraser found other ways of progressing west, eventually using the Bella Coola River to reach the an inlet of the Pacific Ocean on 20 July 1793. In doing so he completed the first recorded crossing of North America north of Mexico. Mackenzie's wish to continue west to the open ocean was prevented by the opposition of the Nuxalk Nation, but on 22 July he painted a rock at the westernmost point he reached with the words "Alexander Mackenzie, from Canada, by land, the twenty-second of July, one thousand seven hundred and ninety-three!" The words have since been carved into the rock.
Alexander Mackenzie was knighted for his work in 1802 and he served in the Legislature of Lower Canada from 1804 to 1808. In 1812, Mackenzie married and returned to Scotland. He died in 1820 and is buried at Avoch on the Black Isle.