Original Journals of the Lewis and Clark Expedition, 1804-1806; Printed From the Original Manuscripts in the Library of the American Philosophical Society and by Direction of its Committee on Historical Documents, Together With Manuscript Material of Lewi

Meriwether Lewis (18 August 1774 - 11 October 1809) was an American explorer, soldier, politician, and public administrator, best known for his role as the leader of the Lewis and Clark Expedition. Lewis was appointed as Secretary to the President by President Thomas Jefferson in 1801. He resided in the presidential mansion, and frequently conversed with various prominent figures in politics and the arts. During the Lewis and Clarke expedition, he explored the territory of the Louisiana Purchase, established trade with, and sovereignty over the Indigenous communities near the Missouri River, and claimed the Pacific Northwest and Oregon Country for the United States before European nations. Lewis also collected scientific data, and information on Indigenous nations.