This Week in History: May 14, 1804

Lewis and Clark

Lewis and Clark Expedition Begins

Over the course of the years 1804 to 1806, Lewis and Clark traveled west from St. Louis to what would become Bismarck, North Dakota, then up the Missouri River and across the Rocky Mountains. They then followed the Columbia River to the Pacific Ocean, where they spent the winter of 1805. After this they returned eastward, splitting up in mid-1806. Lewis explored the northern tributaries of the Missouri River and Clark descended the Yellowstone River. The Corps of Discovery reached its end in St. Louis in September of 1806.

The information gathered by Lewis, Clark, and their team led to a better understanding of the people, animals, and natural resources of the West. In addition to conducting a natural history survey, documenting the region’s flora, fauna, soils, and minerals, the Corps of Discovery also mapped the new territory, which facilitated a greater study of the area. Lewis, in particular, focused on ecological descriptions and natural history discoveries.

Another key accomplishment came from the observations of and interactions with the Native Americans. Though Jefferson wanted the men to locate tribal delegates willing to travel to Washington, DC, to meet the president, this particular request proved difficult. However, Lewis and Clark learned much about the breadth of Native American tribes living in the region, including their ways of life, wide settlements, and extensive trade networks.

The tribes already had intertribal trade networks that included regional market centers and the trade of surplus agricultural production for items such as guns and horses. Unexpected gender roles, both in trade and in wider Native American society, were also a source of revelation for the Corps of Discovery. Much of Lewis and Clark’s diplomatic efforts focused on trade and trade alliances. The knowledge gained—especially related to trade—proved valuable for future interactions.

Lewis and Clark were also tasked with creating ethnographies and cartographies. The pair put together estimates of the Native American tribes and their populations, while recording data about many aspects of Native American life from language to games played and plants used and modified. Other geographic and cultural data recorded included numbers of villages, warriors, and names of countries. The pair also reported on how tribes used political and military power, and how these powers were passed from generation to generation. This information proved valuable as interactions with western tribes increased.

When maps and reports from the Corps of Discovery were published in subsequent years, further exploration began in the region. This led to much settlement and development during the nineteenth century. The Corps of Discovery fostered belief in America’s “Manifest Destiny” to spread across the continent and created excitement about American migration. The maps charted the way west for those who wished to explore and settle new areas.

The methods used by Lewis and Clark to document topography and resources such as flora and fauna became the model for later surveys. Such bodies as the U.S. Army Corps of Topographical Engineers and the U.S. Geological Survey employed their methodologies later in the nineteenth century. The comprehensive field survey method used by the expedition was employed by future American explorations in North America and other locations around the globe.

The Travels of Capts. Lewis and Clarke (Excerpt). (2015). In J. Stock (Ed.), American Eras: Primary Sources (Vol. 5, pp. 355-360). Farmington Hills, MI: Gale. Retrieved from

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