Thomas Jefferson, by Charles Willson Peale. Philadelphia, 1791. Source - Independence National Historical Park Collection, Philadelphia.
What were the effects of the expedition by Lewis and Clark? It depends on your perspective. To the Native Americans, it was the beginning of an end. Their lives will be changed forever by their contact with the fur traders, soldiers, and missionaries that follow in the wake of the Lewis and Clark expedition. Certainly the changes will be gradual, but changes none the less.
The changes will be no less profound for European Americans. President Jefferson's orders were far-reaching. While Lewis and Clark did not discover a Northwest Passage or start the western fur trade or overland immigration, they certainly influenced the latter two movements. They provided valuable information about the topography, the biological sciences, the ecology, and ethnic and linguistic studies of the American Indian. The mysteries of the vast area known as the Louisiana Purchase quickly disappeared after Lewis and Clark.
Geographic discovery was an essential goal that Jefferson set for the expedition. Lewis and Clark recorded a wealth of scientific knowledge as they noted significant geographic features, made detailed route maps, and recorded their observations of longitude and latitude. Lewis performed most the astronomical duties and Clark charted the course and drafted expedition maps.
Jefferson was especially concerned that Lewis and Clark establish good connections with the Indians and carry out linguistic and ethnological studies. Consequently, they held several councils with the Indian tribes they met on their journey. The Americans wanted to open the door to diplomatic relations and gain access to trading rights with the Indians too. They were instructed to notify the Indians of the new sovereignty of the United States under the terms of the Louisiana Purchase. In making these contacts, they hoped to shift trade away from the Spanish, French, English, and Russian competitors and toward American interests. Lewis and Clark were viewing trade as a long-term venture, while the Indians wanted an immediate exchange or merchandise.
Lewis and Clark also were interested in aspects of ecology. They noted the land’s prospects for future agricultural use, while also studying plant and animal life, noting mineral deposits, and recording the country's climate.
They also had some noteworthy accomplishments in the field of biological sciences. Lewis and Clark were the first to describe in detail the many plant and animal species new to science. They also provided a better understanding of the range, habits, and physical characteristics of many know species.
Above all else, it is an American story. An odyssey all Americans can share. There is something in the Lewis and Clark expedition for everyone. If you're interested in science, you are introduced to new plants, new animals, and new territory. If you are interested in Native Americans, you learn about the American Indian culture before it is transformed by contact with white Americans. You can share in the excitement and the dangers encountered by the expedition. There is a tremendous caste of characters — a black slave, a young Indian women, and white American males. All are working together to achieve a common purpose.