Via the Louisiana Purchase the United States acquired more than 2,000,000 km2 (800,000 square miles) of territory from France in 1803 for $15 million. The French territory of Louisiana included far more land than just the current US State of Louisiana; the lands purchased contained parts or all of present-day Arkansas, Missouri, Iowa, Minnesota west of the Mississippi River, North Dakota, South Dakota, Nebraska, Oklahoma, nearly all of Kansas, the portions of Montana, Wyoming, and Colorado east of the Rocky Mountains, the portions of southern Manitoba, southern Saskatchewan and southern Alberta that drain into the Missouri River, and Louisiana on both sides of the Mississippi River including the city of New Orleans.

History

In 1802, U.S. President Thomas Jefferson wanted to purchase New Orleans. The city of New Orleans controlled the Mississippi River, which was already important for shipping goods to and from the parts of the USA west of the Appalachian Mountains. Through a treaty with Spain, American merchants had "right of deposit" in New Orleans, meaning they could use the port for their goods. Napoléon Bonaparte returned Louisiana to French control from Spain (Louisiana had been a colony of Spain since 1762). Americans were fearful that they would lose their rights of use to New Orleans. The Jefferson administration decided that the best way to assure long term access to the Mississippi would be to purchase the city of New Orleans and the nearby portions of Louisiana east of the Mississippi. Jefferson sent James Monroe and Robert R. Livingston to Paris to negotiate such a purchase.

From Frank Bond, "Louisiana" and the Louisiana Purchase.
Government Printing Office, 1912 Map No. 4.

The renewal of the war between the British and French appeared inevitable, and Napoléon had just faced a major military setback in the west when his army sent to subdue the rebellion in Haiti was destroyed by a combination of yellow fever and fierce resistance led by Toussaint L'Ouverture. In addition, the weakness of French naval power in comparison with Britain made France's North American possessions difficult to resupply and created the possibility that the British could invade Louisiana from Canada. All of this made Louisiana less valuable to Napoleon, while increasing his need for more money.

The idea of an offer to purchase New Orleans stemmed from the extremely close relationship between France and the United States. Napoléon then had the most powerful army in Europe and saw the sale of his American territory as a goodwill gesture and a strategic move against the British. A strong America would be a buffer against Britain when the inevitable showdown came. (There is also the possibility that he wished to encourage the USA to assist with his embargo on strategic resources reaching the British, the Continental policy.) Napoléon decided to sell the entire territory to the United States. The American negotiators were prepared to spend $2 million for New Orleans, but were dumbfounded when the entire region from the Gulf of Mexico to Rupert's Land and from the Mississippi River to the Rocky Mountains, which would double the size of the USA, was offered for $22.5 million. The cost of the land was less than 3 cents per acre ($7 per square kilometer). Although not authorized to make such a large purchase, Monroe and Livingston recognized the unique historic opportunity and accepted Napoléon's offer. The treaty was signed on April 30, 1803 and announced to the American people on July 4. President Jefferson immediately approved the treaty, and the congress ratified the treaty on October 20, 1803. Napoléon added the money from the sale of the Louisiana Territory to his massive war chest and began his plans to control the European continent. Between 1805 and 1807 he defeated Austria, Prussia, and Russia and made himself master of most of Europe.

The American purchase of the Louisiana Territory was not accomplished without domestic opposition. The Federalists strongly opposed the purchase, and favored close relations with Britain rather than Napoléon. The Federalists argued that the purchase was unconstitutional, and that the US had paid a large sum of money just to declare war on Spain. It was also feared that the political power of the Atlantic seaboard states would be threatened by the new citizens of the west, a clash of western farmers versus the merchants and bankers of New England. A group of Federalists led by Massachusetts senator Timothy Pickering went so far as to plan a separate northern confederacy and offered Vice-President Aaron Burr the presidency of the proposed break off if he would persuade New York to join. Alexander Hamilton helped stop the northern secession and showed hostility towards Burr, which grew in the 1801 election and ended with Hamilton's death in a duel with Burr in 1804.

France turned New Orleans over to the USA on December 20, 1803. In March 10, 1804 a formal ceremony was conducted in St. Louis, to transfer ownership of Louisiana Territory from France to the United States.

See also: History of United States

Public domain picture from U.S. National Archives and Records Administration