Facsimile of “A Map of part of the Continent of North America.” 1810.

William Clark (1770-1838), whose family resided for a time near Charlottesville, grew up in Virginia and Kentucky. Clark received little formal education but he did learn frontier skills and the art of surveying. He followed in the footsteps of his older brother, George Rogers Clark, the great hero of the Revolutionary War, by joining the army and serving a command on the Mississippi River. William Clark was Meriwether Lewis’s commanding officer in 1795-96 and he and Lewis became friends. They remained friends after Clark resigned his army commission. While Lewis was serving as President Jefferson’s personal secretary, Clark visited him and also met Jefferson.

The three men may have discussed Jefferson’s dream of finding a route to the Pacific Ocean. After Jefferson selected Lewis to lead the expedition to the Pacific, Clark eagerly accepted Lewis’s offer to share the command; Jefferson wrote to a government official that "William Clarke accepts with great glee the office of going with Capt. Lewis up the Missouri." Following the expedition, Clark served as superintendent of Indian Affairs and then governor of the Missouri Territory.

In preparation for the expedition to the Pacific, William Clark trained himself to be an able cartographer. During the winter of 1803-1804 Clark studied the maps and geographic information that Lewis brought to Camp Dubois near St. Louis. He also practiced using the sextant and the octant. William Clark was a fast learner, perhaps due to his surveying experience. Before the Corps of Discovery left the St. Louis area, Clark produced a map of part of upper Louisiana and a table of distances to the Pacific coast. By the spring of 1805, when the expedition team had advanced as far as Fort Mandan, Clark had produced the route maps of the Missouri River from St. Louis and a general map of the Missouri River system and the Northwest.

Twenty-eight arduous months after setting off, the Lewis and Clark Expedition returned to a triumphant welcome in St. Louis on September 23, 1806. Upon hearing the news of the success of the expedition, Jefferson wrote of his "unspeakable joy." Lewis and Clark hurried on to Washington. Clark brought with him an updated map of the West which he had prepared at Fort Clatsop on the Pacific coast during the previous winter. Nicholas King copied both the Fort Mandan map and the updated map made at Fort Clatsop.

Over the next few years Clark continued to improve on his map, producing in 1810 the version in the exhibition. This map includes information gathered from the additional explorations in 1807-1808 of the Yellowstone basin by Corps of Discovery members George Drouillard and John Colter. Clark’s 1810 map also incorporates the findings from recent expeditions to the southern Rockies and upper Mississippi River by Zebulon Pike; James Wilkinson’s expedition on the Arkansas River; William Dunbar’s explorations of the Ouachita River; and Thomas Freeman’s journey to the Red River.

William Clark’s map surpasses its predecessors by presenting a radically new and remarkably accurate view of the upper Missouri and its connections with the Columbia River basin. The map is also notable for its representation of the western mountains as multiple ranges rather than a single range of mountains. This advance in geographical knowledge finally extinguished the idea of a Northwest Passage to India via the Missouri River and marked the end of the long-cherished hope of finding a short portage to the Pacific.

The map on display is a 1950 facsimile of the 1810 manuscript map by William Clark. Clark’s original map is in the William Robertson Coe Collection of Western Americana, Yale University Library.

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