The United States and France completed the largest land deal in history on Dec. 20, 1803, in an agreement known as the Louisiana Purchase.
The Louisiana territory contained all or parts of 15 modern-day states and spread over roughly 828,000 square miles west of the Mississippi River from the coast of Louisiana into southern Canada. The United States government purchased the territory from France for $15 million, or less than 3 cents an acre.
France first ceded the territory to Spain in 1762 during the Seven Years’ War. The French military leader Napoleon Bonaparte took control of his country in 1799, a decade after the French Revolution began. Bonaparte convinced Spain’s King Charles IV to return Louisiana to France for several concessions, including an agreement that France would not trade Louisiana to another foreign power.
After hearing of the transaction, U.S. President Thomas Jefferson directed U.S. Minister to France Robert Livingston to approach the French government with an offer to buy the port city of New Orleans. The U.S. had agreements with Spain that allowed Americans living along the Mississippi to use the river and the port city to travel and trade goods. Jefferson worried that the U.S. would lose access to New Orleans under French rule.
Jefferson arranged to send James Monroe to Paris to join Livingston and work out an agreement. Livingston used the threat of a potential U.S.-British alliance to push France into bargaining, and on April 11, 1803, French Foreign Minister Charles Talleyrand agreed to enter discussions. Tensions between the French and British were high in 1803 — Britain would declare war on France in May — and French officials feared facing both the U.S. and British together in a war.
Monroe and Livingston worked out an agreement to purchase much more than New Orleans. The U.S. diplomats arranged to pay France $11,250,000 for the Louisiana territory as well as pick up the cost of all American claims against France in the region for an additional $3,750,000.
After word of the deal reached the U.S., lawmakers debated whether the president even had the authority to negotiate such a deal. The Senate averted a Constitutional crisis and international incident by ratifying the treaty 24-7 on Oct. 20. Two months later, on Dec. 20, France officially transferred the Louisiana Territory to the U.S.
The deal roughly doubled the size of the United States and encouraged westward expansion into a resource-rich land. Exploring and mapping out the territory would later fall to the American explorers Meriwether Lewis and William Clark.
