The Louisiana Purchase nearly doubled the size of the United States in 1803.
President Thomas Jefferson’s administration purchased the territory from France for $15 million, or roughly three cents per acre. The agreement was signed in Paris on April 30, 1803, and the United States formally took possession later that year.
Jefferson originally sent James Monroe and Robert Livingston to seek the port of New Orleans and nearby areas. France’s decision to sell the entire Louisiana territory, influenced by financial pressures and the failure to reestablish a French empire in North America, produced a much larger deal than American negotiators expected.
The purchase secured control of the Mississippi River and New Orleans, vital routes for western farmers and merchants. The territory included land that later became all or part of fifteen present-day states, although its boundaries and ownership were still subject to later surveys and disputes.