In 1803 the United States of America negotiated the purchase of the Louisiana Territory from France. At that time the western boundary of the United States was the Mississippi River. However, even at that early date there were many Americans who were residents of the Louisiana Country, a vast, roughly triangular-shaped area which extended from New Orleans to the Canada–United States border. St. Louis was already a thriving river city. The Chouteaus, the Lacledes, and other early settlers had already established a profitable fur trade with the Indians who roamed the rich fur country along the Missouri River.