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Louisiana Purchase: A Legislative Timeline

This timeline examines the role of the U.S. Congress in the Louisiana Purchase during the years 1802 to 1807. The digital images and congressional documents referenced in the timeline are available online from the Library of Congress.


In the year 1803, the United States purchased the Louisiana Territory (approximately 828,000 square miles in North America) from the country of France for $15 million. The signing of the Louisiana Purchase treaty on April 30, 1803 (8 Stat. 200) [PDF] doubled the size of the United States and promoted further westward expansion.

Le Page du Pratz, contributor. A map of Louisiana, with the course of the Missisipi, and the adjacent rivers, the nations of the natives, the French establishments and the mines; by the author of ye History of that colony. 1757. Library of Congress Geography and Map Division.

This timeline examines the role of Congress in the Louisiana Purchase from 1802 to 1807, including ratification of the treaty, establishment of a territorial government, confrontation with Spain over boundary issues, and its limited role in the Lewis and Clark Expedition. The congressional documents contained within this timeline come from the American Memory collection A Century of Lawmaking for a New Nation and the digital collections at the Library of Congress.