06/23/2026
Without much doubt, Thomas Jefferson and Meriwether Lewis were on the same page when it came to the expedition into the Northwest. For over two years they had many discussions about this exciting adventure throughout the time that Lewis worked as the president’s secretary in the President’s House.
However, Jefferson wasn’t about to take any chances and felt compelled to write a detailed instructional letter to the young captain on June 20, 1803. National expansion and economic development dominated the president’s thoughts, and he wanted to ensure Lewis had no doubt about what mattered most. In paragraph one, Jefferson couldn’t be more clear: “The point of your mission is to explore the Missouri river, & such principal stream of it, as, by it’s course and communication with the waters of the Pacific ocean, whether the Columbia, Oregan, Colorado or any other river may offer the most direct & practicable water communication across this continent for the purposes of commerce.”
Mr. Jefferson then goes into greater detail on a long list of topics, including geographic objectives, diplomatic goals with the Native peoples, his expectations of scientific observations, prioritizing safety of the party, and the gathering of information for commercial benefit.
We don’t know Lewis’ reaction to the letter. He was extremely busy, for sure, as he continued to finalize all the plans and supplies for the journey. He would remain in Washington City until July 5 when he would depart for Harpers Ferry, where weapons, ammunition, and military supplies were being collected.
To read a transcript of Jefferson’s entire instructional letter, go to the Library of Congress: https://www.loc.gov/exhibits/lewisandclark/transcript57.html.
Image: Portrait of Thomas Jefferson by John Trumbull in 1788, within the collection of the Metropolitan Museum of Art, New York.
Image Description: A stoic Jefferson is dressed in a black coat, gold vest, and white ruffled shirt. He is shown wearing a white, powdered wig, common for the period. He is looking to the viewer’s right. The background is plain white. The paint has numerous long cracks throughout the image.
