The Louisiana Purchase

Napoleon, having lost Haiti and preparing for war in Europe, agrees to sell the United States the vast lands west of the Mississippi for fifteen million dollars. The purchase doubles the country's area and gives it the mouth of the Mississippi with New Orleans, vital to its trade. President Jefferson, doubting his own right to such a bargain, nevertheless carries it through the Senate and fits out the Lewis and Clark expedition to the Pacific. For the Indian nations of the West it is the beginning of dispossession; for the country, a new quarrel over where slavery shall be allowed.