Excerpt from "Jefferson's Instructions to Lewis"

Delivered April 1803; published in The Journals of Lewis and Clark,
edited by Bernard DeVoto, 1953

The Louisiana Purchase, the vast expanse of land acquired by the United States in 1803, was unknown country to all but a few people. Not long after the purchase, President Thomas Jefferson (1743–1826; served 1801–9) ordered that the area be explored, and within a few years, the explorers' reports would make the region less mysterious to Americans. Jefferson had long been interested in exploration of the land west of the Mississippi River. In the 1790s, land-hungry pioneers had flooded into the region just west of the Appalachian Mountains, creating settlements as far west as the Mississippi River. It seemed inevitable that Americans would eventually move across the Mississippi. By the late 1790s, people in Britain, France, and Spain thought that the United States might one day reach all the...