A Convention between the United States of America and the French Republic (Louisiana Purchase), April 20, 1803
The 1803 Louisiana Purchase was an agreement by which the United States acquired the entire Louisiana territory—over 828,000 square miles—from France. It consisted of three separate parts: a treaty of cession and two conventions providing for the exchange of money. On October 20, 1803 the Senate ratified the purchase thus doubling the size of the United States and making land available west of the Mississippi River for American exploration and expansion.
A Convention between the United States of America and the French Republic Concerning Debts Owed by France to Citizens of the United States, April 20, 1803; Records of the U.S. Senate, RG 46.