Gathering Intelligence
The Corps of Discovery
The Winter  of 1803-1804

One of the top priorities of the Corps of Discovery during the winter of 1803-1804 was to gather as much intelligence about what lay ahead as possible. Lewis and Clark weren’t the first men to explore the Missouri River. Native American cultures had inhabited the area for dating back as far as 8,000 years ago, with more recent tribes inhabiting the region for hundreds of years. The Corps of Discovery also wasn’t the first expedition to travel overland to the Pacific Ocean. That claim to fame belongs to an expedition led by Alexander MacKenzie, a fur trader and explorer for the North West Company in Canada. There were two principal sources of information the Corps had to draw from: previous expeditions and the fur trading industry.

European Expeditions of the Missouri River 1714-1797

There were at least five documented expeditions of the Missouri River by European explorers since the time Jacques Marquette passed the mouth of the river in 1673. The first was led by Etienne Bourgmont, a French fur trader, who traveled the Missouri River in 1714 at least to the mouth of the Platte River in present day Nebraska, and who afterwards wrote "The Route to Be Taken to Ascend the Missouri River." In 1790 Jacques D’Eglise reached the Mandan Indian villages of present day North Dakota and the site of the winter camp of the Corps of Discovery in 1804-1805. D’Eglise reported back to Spanish officials that English fur traders were operating in the area.

The Spanish were alarmed by D’Eglise’s reports and took steps to oust the British from their territory, extend their claims to the Pacific Ocean, and promote the fur trade. In 1793 they chartered the "Company of Discoverers and Explorers of the Missouri," commonly known as the Missouri Company, to promote the fur trade in the Upper Missouri region (present day North Dakota and Montana.) They also offered a prize to the first Spanish subject to reach the Pacific Ocean via the Missouri River. In 1794 and 1795 expeditions were undertaken to reach the Mandan villages led by Jean Baptiste Truteau and Antoine Simon Lecuyer de la Jonchšre, both of which failed to reach their objective. In 1795 an expedition led by James Mackay and John Evans was directed to finish the journey started by Truteau who managed to reach present day South Dakota. The Mackay-Evans party made it to present day Omandi, Nebraska where they built quarters for the winter of 1795-1796. In the spring of 1796 Evans journeyed to the Mandan villages area, chased out the British traders and occupied their fort. The Mackay-Evans expedition returned to St. Louis as heroes in May of 1797.

Both the Truteau and Mackay-Evans expeditions returned with journals of their travels. Although Lewis and Clark initially placed value on the Truteau journal, the information provided by the Mackay-Evans expedition became the primary source of information for the Corps. The Mackay-Evans journals were in French and were translated by Cahokian John Hay. Although the Lewis had the latest maps available when he left the east coast, the maps from Mackay-Evans provided the most complete and up to date information of the Missouri River region and copies were made for the expedition.