One of Thomas Jefferson's goals was to find "the most direct and practicable water communication across this continent, for the purposes of commerce." He also placed special importance on declaring US sovereignty over the land occupied by the many different Indian tribes along the Missouri River, and getting an accurate sense of the resources in the recently completed Louisiana Purchase. The expedition made notable contributions to science, but scientific research was not the main goal of the mission.
During the 19th century, references to Lewis and Clark "scarcely appeared" in history books, even during the United States Centennial in 1876, and the expedition was largely forgotten. Lewis and Clark began to gain attention around the start of the 20th century. Both the 1904 Louisiana Purchase Exposition in St. Louis and the 1905 Lewis and Clark Centennial Exposition in Portland, Oregon showcased them as American pioneers. However, the story remained relatively shallow until mid-century as a celebration of US conquest and personal adventures, but more recently the expedition has been more thoroughly researched.
In 2004, a complete and reliable set of the expedition's journals was compiled by Gary E. Moulton. In the 2000s, the bicentennial of the expedition further elevated popular interest in Lewis and Clark. As of 1984, no US exploration party was more famous, and no American expedition leaders are more recognizable by name.