David Thompson (explorer)

Lore & Background

David Thompson was born in Westminster, Middlesex, to English parents David and Ann Thompson. After his father died when he was two, his mother placed him and his older brother in the Grey Coat Hospital, a school for the disadvantaged. He graduated to the Grey Coat mathematical school, where he learned navigation and surveying, including trigonometry, geometry, and the use of nautical instruments. In 1784, at age 14, the Grey Coat treasurer paid the Hudson's Bay Company five pounds, and Thompson became an apprentice clerk for seven years. He sailed for North America on 28 May 1784.

Thompson arrived at Churchill on 2 September 1784 and worked as a clerk for the Hudson's Bay Company. He learned to keep accounts, calculate fur values, and track supplies. In 1787, he joined a trading group heading south and west, reaching the foothills of the Rocky Mountains. He wintered with the Piegan Blackfeet Indians in 1787, learning their language. On 23 December 1788, he fractured his tibia and spent two winters convalescing at Cumberland House, where he refined his surveying skills under Philip Turnor. During this time, he lost sight in his right eye, though the historical record does not definitively link this to his injury or convalescence. In 1790, he requested surveying tools instead of fine clothes as a parting gift from the company. He completed his first significant survey in 1792, mapping a route to Lake Athabasca. In 1794, he was promoted to official surveyor of the Hudson's Bay Company. He left the company on 23 May 1797, walking 130 kilometers in the snow to join the North West Company.

With the North West Company, Thompson surveyed part of the Canada-US boundary in 1797. By 1798, he had completed a survey of 6,750 km from Grand Portage to the headwaters of the Assiniboine and Mississippi rivers. In 1798, he was sent to establish a trading post at Red Deer Lake. On 10 July 1804, he was made a full wintering partner of the North West Company. In 1806, the company charged him with finding a route to the Pacific. In June 1807, he crossed the Rocky Mountains and began surveying the Columbia basin, establishing trading posts such as Kootenae House, Kullyspell House, and Saleesh House. His maps of the Columbia River basin east of the Cascade Mountains remained useful into the 20th century.

Reader's Guide

David Thompson's significance lies in his unparalleled contributions to the mapping of North America. Over his career, he traveled 90,000 kilometers and mapped 4.9 million square kilometers, a feat that earned him the description 'greatest practical land geographer that the world has produced.' His surveys of the Canada-US boundary after the Jay Treaty helped resolve territorial questions, and his detailed maps of the Columbia River basin were so accurate they remained in use into the 20th century. Thompson's work for the Hudson's Bay Company and later the North West Company extended fur trading territories and provided crucial geographic knowledge of the interior. His legacy endures as a foundational figure in the cartographic history of North America, though his contributions were often underappreciated in his lifetime.

Did You Know?

• Thompson was known to some native people as 'Koo-Koo-Sint' or 'the Stargazer.'
• He lost sight in his right eye while convalescing from a fractured tibia at Cumberland House, though the exact cause is not definitively known.
• He walked 130 kilometers in the snow to defect from the Hudson's Bay Company to the North West Company.