1762 - In the aftermath of the French and Indian War, France loses the Louisiana Territory to Spain. When Spain returns the land to France in an 1801 treaty, Americans worry about what the aggressive Napoleon Bonaparte might do with it. In response, President Thomas Jefferson orders U.S. Minister Robert Livingston to negotiate the purchase of the strategic port of New Orleans from the French. When France offers to sell the entire Louisiana Territory instead, Jefferson moves swiftly to close the deal. On May 2, 1803, the United States signs a treaty with France, acquiring the Louisiana Territory for 15 million dollars. The land deal doubles the size of the United States, adding 828 million square miles to its territory. At a cost of less than three cents per acre, the Louisiana Purchase becomes one of Thomas Jefferson’s most notable achievements as President of the United States.