David Thompson was born in London in 1770. His father died when he was only two and at seven David was sent to a charity school.

At 14, he was apprenticed as a clerk to the Hudson's Bay Company. He was first sent to Fort Churchill on Hudson's Bay and then to York Factory before being transferred to the Saskatchewan River. In 1787, he spent the winter with the Peigan Indian tribe, learning their language and culture.

The next year he broke his leg and while recovering at Cumberland House, he learned surveying and astrology from the Hudson's Bay Company's astronomer.

When his leg healed, David Thompson began in earnest his legendary career exploring, surveying and mapping the uncharted areas of western Canada. To accomplish this task, he used a sextant, a compass, thermometers, watches, and a Nautical Almanac.

At age twenty-four he had already surveyed most of northern Manitoba and Saskatchewan for the Hudson Bay Company, and he resigned to join the more adventurous North West Company. In his first year with the NWC he traveled from the Missouri and Mississippi Rivers to Sault Ste. Marie and back to Grand Portage (6500km).

David married Charlotte Small, a Metis woman. They were married 60 years and had 13 children, their first was born at Rocky Mountain House in 1801.

For the next four years, Thompson explored the Peace River area to Fort William on Lake Superior.

In the fall of 1806, he set out to find a practical route to the Pacific Ocean. In a three year journey, he surveyed and establish trading posts in British Columbia, Washington, Oregon, Idaho, and Montana before crossing the Athabasca Pass and traveling down the Columbia River, David reached the mouth of the Columbia at the Pacific Ocean on July 15th, 1811.

David Thompson was Canada's first and possibly its greatest geographer.