The Louisiana Purchase has been described as the "greatest real estate deal in history." In 1803, The United States government purchased the Louisiana Territory from Napoleon I of France for 60 million Francs, or, about $15,000,000. $11,250,000 was paid directly and the remainder was covered by French debt to U.S. citizens.

The Louisiana Purchase was consumated in order to secure free navigation of the Mississippi River. President Jefferson sent two negotiators - James Madison and Robert Livingston to France to convince Napoleon I to sell the city of New Orleans. Time was of the essence because many viewed Napoleon's acquisition of the Louisiana Territory as a means to invade the United States. Surprisingly, Napoleon offered not only New Orleans, but the entire Louisiana Territory for sale. Because a constitutional amendment authorizing the acquisition would take too long, and because Napoleon wanted the deal finalized quickly, Jefferson held the issue to a vote. Americans overwhelmingly voted in favor of purchasing the Louisiana Territory. Its 800,000 square mile area quickly doubled the size of the United States. Soon after the acquisition, Jefferson sent Meriwether Lewis and William Clark on an expedition through the new lands in which hundreds of new animals were discovered as well as Native American tribes and a route to the Pacific Ocean.