As America expanded westward in the late 18th and early 19th centuries, the port of New Orleans, which controlled all trade passing through the Mississippi River, became vitally important to the United States. In 1802, Jefferson became concerned that Napoleon would cut off U.S. shipping, and that French influence in the Americas would be too great if France possessed both Louisiana (which was scheduled to be given by Spain to France in 1803) and New Orleans (which France already possessed). As a result, Jefferson sent Robert R. Livingston to France to negotiate the purchase of New Orleans for up to $10 million. To Jefferson's surprise, France in 1803 instead offered to sell all of Louisiana for only $15 million.
