William Clark

William Clark was central to the success of the Corps of Discovery expedition not only during the two years spent crossing the continent but also because he produced maps of the west long after his return. , His three maps of the Western United States were produced from sketches made during the expedition. He completed detailed maps during the winters of 1804 and 1805 in Fort Mandan and between 1805 and 1806 in Fort Clatsop. The third map was finished in St. Louis between 1809 and 1810. Clark had an extraordinary ability to illustrate the landscapes he observed onto a one-dimensional map as well as a natural instinct to determine the course of rivers beyond his sight. Clark's maps accurately showed the west as having multiple mountain ranges, rather than a single range, as was commonly believed at the time. , His brother George Rogers Clark recommended him to Thomas Jefferson after turning down Jefferson's offer to lead the expedition. Jefferson then recruited Meriwether Lewis. Lewis had served under Clark in the military, after which the two men became friends. Lewis offered Clark the opportunity to join the Corps. Clark responded to Lewis accepting the offer. , I will cheerfully join you in an “official Carrector” as mentioned in your letter and partake of the dangers, difficulties and fatigues and I anticipate the honers and rewards of the result of such an enterprise… , , July 18, 1803 , An experienced woodsman, military commander and surveyor with an outgoing and even temperament, Clark complemented Lewis’s skills and traits to provide a strong shared leadership of the Corps.