Louisiana Purchase: U.S. Doubled in Size

The French explored and claimed Louisiana in the 17th century, and held it until their loss in the French and Indian War in 1763. The Treaty of Paris, which ended that war, transferred a large area of French territory—the section west of the Mississippi River that later became the Louisiana Purchase territory—to Spain, who held it until 1800. Then Napoleon regained Louisiana for France with a secret treaty with Spain, one that was not revealed until shortly before France sold the entire area to the United States in 1803. Napoleon needed Louisiana because it served as a "breadbasket" for the immensely valuable sugar islands of the Caribbean that France controlled. The sugar-producing land was so valuable on islands such as Hispaniola and Martinique that all the farmland was used for that one crop, and foodstuffs for the planters and slaves had to be imported.

Article continues after this newspaper image from the Oct. 19, 1803, issue of the Republican (Baltimore, Maryland)

Unfortunately for Napoleon, the revolutionary spirit of the age had reached the slave population of Haiti, the largest of the French Caribbean possessions. Black slaves successfully revolted against the French plantation owners. France knew that slavery had to be restored in order to make the colony profitable again. Under the leadership of Toussaint L'Ouverture and others, and aided by tropical diseases, the Haitian rebels successfully repelled attempts by Napoleon's generals to recapture the colony. By 1802, with the growing slave rebellion and the loss of Haiti's plantation system, Napoleon realized the sugar islands were not as valuable to France, and therefore it no longer needed Louisiana to supply the islands. He decided he would be willing to sell Louisiana, including the valuable port of New Orleans, ending French dreams of a North American empire.

Foreign control of New Orleans, whether Spanish or French, interfered with American farmers that sought to ship goods down the Mississippi River, since treaties guaranteeing traders' "right to deposit" goods at New Orleans were often violated. In 1803, President Thomas Jefferson sent James Monroe and Robert Livingston to negotiate purchase of the port of New Orleans. Napoleon stunned the American diplomats by offering to sell not only the port but the entire Louisiana territory, which encompassed portions of 15 modern-day U.S. states and two Canadian provinces. The price was $15 million plus interest for this vast area, stretching from the Gulf of Mexico to Canada, and from the Mississippi River to the Rocky Mountains. The Louisiana Purchase Treaty was signed on April 30, 1803. The purchase tested Jefferson's strict constructionist principles, stirred sectional opposition, and doubled the size of the United States. President Jefferson then arranged the Lewis and Clark Expedition to explore America's vast new territory.