The expedition was conceived by President Thomas Jefferson at his home in Monticello and Meriwether Lewis undertook major preparatory activities at Philadelphia, Pittsburgh, and Wheeling. Most importantly, the enterprise became truly the Lewis and Clark Expedition when the captains shook hands at the Falls of the Ohio, where William Clark and other members of his family resided, including his older brothers Jonathan and George Rogers Clark. It was in Clarksville, near George’s cabin, that Meriwether Lewis and William Clark established their base camp and recruited, trained, and swore the nucleus of the Corps of Discovery into military service. It was from Clarksville, at the mouth of Mill Creek, that they embarked for the West on October 26, 1803, and to where they returned on November 5, 1806, and were greeted by George Rogers Clark, Jonathan Clark, and other dignitaries.
The St. Louis claim overlooked the fact that Camp Dubois, the Corps of Discovery’s 1803-1804 winter camp, was located at the mouth of the Wood River, opposite of the Missouri River. The site was then in the portion of Indiana Territory that later became the state of Illinois.
That claim is a masterpiece of marketing used to shape a historical narrative. Yes, the actual exploration began in the St. Louis vicinity. Thus, in the late nineteenth century and the opening years of the twentieth, civic leaders in St. Louis capitalized on the approaching centennials of the Louisiana Purchase and the Lewis and Clark Expedition to conduct the Louisiana Purchase International Exposition, commonly known as the St. Louis World’s Fair. The organizers successfully claimed that the expedition began at St. Louis, and years later the National Park Service endorsed it by establishing the Jefferson National Expansion Memorial in the city.
These facts are ample evidence that the Lewis and Clark Expedition began at Clarksville, Indiana, and the Falls of the Ohio.