On April 30, 1803, the United States and France signed the Louisiana Purchase treaty. The agreement transferred a vast territory west of the Mississippi River to the United States for about $15 million. The purchase nearly doubled the size of the country. It opened new lands for settlement and exploration, including the later Lewis and Clark expedition. The deal raised constitutional questions, since the power to acquire territory was not clearly spelled out. Despite some opposition, the purchase became one of the most significant land deals in American history and reshaped the map of North America.
