The Lewis and Clark expedition, which was known as the Corps of Discovery Expedition in the past, was the first-ever American expedition to cross into what is now the western portion of the United States. It was commissioned by Thomas Jefferson in 1803 to find “the most direct and practicable water communication across the continent, for the purposes of commerce.”
Expedition members encounter Chinook Native Americans on the Lower Columbia River, October 1806
President Jefferson commissioned the expedition in the wake of the Louisiana Purchase, which involved the sale of no less than 828,000 square miles of the Louisiana territory from the French to the Americans. It was sold for 68 million French francs – the equivalent of $300 million in today’s money (For more explanations continue reading below the map).
This is a recreation of Ford Mandan, where members of the Lewis and Clark expedition spent the winter of 1805.
Find out what happened on the trail by clicking on the blue numbers from 1 to 12 on the map below. Click on each number to see a popup window containing information about a particular part of Lewis and Clark's epic journey.
The expedition was led by explorers Meriweather Lewis and William Clark, who led a team of select US Army volunteers to find a practical route across the western half of North America and establish an American presence in the territory. Furthermore, the expedition had secondary objectives to study the territory’s plants, animal life and geography, and establish trade with local Native American tribes.
Following the announcement of the Louisiana Purchase on July 4th, 1803, Lewis headed to Pittsburgh, Pennsylvania to oversee the construction of a keelboat that would be used on the long journey westward. He stopped at Falls of the Ohio to pick up Clark and nine US Army recruits later on that summer before establishing Camp Wood for the winter on the east bank of the Mississippi River. More men were recruited and trained at Camp Wood prior to the onward journey.