Treaty
Louisiana Purchase Treaty
The treaty between the United States and France for the purchase of the Louisiana Territory for $15 million, doubling the size of the nation. While the Lewis and Clark Expedition was already planned before the purchase was finalized, the acquisition of this vast territory gave the expedition even greater urgency and significance as a survey of America's newest possession.
The Louisiana Purchase transferred approximately 828,000 square miles of territory from France to the United States, encompassing all or part of 15 future states. The treaty was signed in Paris and ratified by the U.S. Senate on October 20, 1803. The purchase transformed the Lewis and Clark Expedition from a covert reconnaissance of foreign territory into an official survey of American land, dramatically expanding its diplomatic and scientific mandate.
