The Louisiana Purchase was a huge land purchase by the United States in 1803 which effectively doubled the size of the young nation.
The land, a vast tract of 828,000 square miles, essentially the American Midwest, was bought from France for $15 million.
The land purchase began with President Thomas Jefferson seeking to buy the city of New Orleans, the seaport at the mouth of the Mississippi River.
Envoys sent to France to negotiate a deal for New Orleans were surprised when the French foreign minister, Charles Maurice de Talleyrand, offered to sell France's entire holdings in North America.
The loss of the French colony of Saint Domingue, which became the independent nation of Haiti following a slave rebellion, had prompted the French to abandon their plans for an empire in the Americas.
Jefferson, recognizing the value of the land, made the necessary arrangements, and the sale proceeded, becoming final on December 20, 1803 with the raising of the American flag over New Orleans.
The land in the Louisiana Purchase today encompasses all of six U.S. states and parts of eight others.