Clark follows up his letter of 23 September with a personal letter mentioning that they will be traveling east to Louisville, Kentucky, via Vincennes, Indiana, with a delegation of Mandan Indians, with which Meriwether Lewis will continue on to Washington, D. C. They will be detained for a time in St. Louis wrapping up expedition business and discharging the men. Clark specifically requests that Jonathan have his 23 September letter published.
Letter from William Clark to his brother talks of sending his journal to the President and the Secretary of War, documenting his voyage and discoveries. Includes note stating he has included with the letter: one shirt worn by the Mandan Indigenous women, a few pairs of moccasins, some Mandan "legins", hides from several different animals, corn, tobacco seeds, a Mandan pot, and more, from the western country. He sends compliments from Meriwether Lewis to him and his lady.