In 1803, President Thomas Jefferson sent diplomats to Paris to buy New Orleans. Napoleon, his dreams of a North American empire collapsing, offered to sell something far larger: all of Louisiana, 828,000 square miles stretching from the Mississippi River to the Rocky Mountains. The price was $15 million, less than 3 cents an acre.

Key Takeaways

• Louisiana had passed between France and Spain multiple times before Napoleon pressured Spain to return it to France in 1800 through the Treaty of San Ildefonso.

• Jefferson sent Robert Livingston and James Monroe to Paris authorized to spend up to $10 million for New Orleans and West Florida. They ended up buying everything for $15 million.

• Napoleon sold because a slave revolt in Haiti had wrecked his plans for a New World empire, renewed war with Britain loomed, and he needed funds for his European campaigns.

• The Louisiana Purchase nearly doubled the size of the United States and eventually formed all or part of 15 American states.

• Just five months after the transfer, Jefferson sent Lewis and Clark west from Illinois on May 14, 1804, to explore the new territory all the way to the Pacific.

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FAQ - Frequently Asked Questions

Q1: Why did Napoleon sell Louisiana to the United States?

Napoleon's plans for a French empire in North America collapsed for several reasons. A slave revolt in Haiti devastated French forces and ended French control of the island. War with Britain was looming again, and without naval superiority Napoleon couldn't protect Louisiana from British seizure. He also needed money to finance his European military campaigns. Selling the territory to the Americans solved all three problems at once.

Q2: How much did the Louisiana Purchase cost?

The United States paid $15 million for the Louisiana Territory, which worked out to less than 3 cents per acre. The territory covered 828,000 square miles, or roughly 530 million acres. It was one of the largest and most consequential real estate transactions in history.

Q3: Were Lewis and Clark authorized to buy all of Louisiana?

No. Robert Livingston and James Monroe were authorized to spend up to $10 million to purchase New Orleans and West Florida. When Napoleon's foreign minister offered the entire Louisiana Territory, the two men had to make the decision on their own without consulting Jefferson. They agreed to $15 million, exceeding their budget and their mandate. Jefferson, when he found out, had to stretch his interpretation of presidential power to justify the purchase.

Q4: What states were formed from the Louisiana Purchase?

The Louisiana Territory eventually formed all or part of 15 states: Louisiana, Missouri, Arkansas, Iowa, Minnesota (west of the Mississippi), North Dakota, South Dakota, Nebraska, Kansas, Oklahoma, Colorado (most of it), Wyoming, Montana, and Idaho, as well as portions of New Mexico and Texas.

Q5: What was the Lewis and Clark Expedition?

The Corps of Discovery, led by Meriwether Lewis and William Clark, set out from Illinois on May 14, 1804, just five months after Louisiana officially transferred to the United States. Jefferson commissioned the expedition to explore the new territory, map the Missouri River, find a route to the Pacific, and document the plants, animals, and peoples of the region. The expedition returned in 1806.

A Territory That Kept Changing Hands

Louisiana was a vast territory spanning 828,000 square miles, named for French King Louis XIV by explorer René-Robert Cavelier de La Salle in the late 17th century. Control shifted between France and Spain over the years. During the French and Indian War, France secretly ceded Louisiana to Spain through the Treaty of Fontainebleau to keep it out of British hands. In 1800, Napoleon pressured Spain to return it through the Treaty of San Ildefonso. He had grand plans for a French empire in North America. Jefferson had won the presidency only after the bruising political fight we cover in our episode on the Election of 1800.

Why New Orleans Mattered So Much

American farmers west of the Appalachians depended on the Mississippi River to move their goods to market. New Orleans sat at the mouth of the river and controlled access to it. Whoever held New Orleans held the commercial lifeline of central America. Under Washington, Thomas Pinckney had negotiated American navigation rights on the river when Spain controlled it. Now, the prospect of an expansionist France in control alarmed President Jefferson. In 1802, he instructed his minister to France, Robert Livingston, to negotiate the purchase of New Orleans and the surrounding areas, particularly West Florida. James Monroe was sent to assist. Together they were authorized to spend up to $10 million. The newly acquired territory would be mapped by the journey we cover in our episode on the Lewis and Clark expedition.

Napoleon's Empire Unravels

Napoleon's North American ambitions were crumbling. A massive slave revolt in French-owned Haiti, led by Toussaint L'Ouverture, had proven catastrophically costly for French forces. Renewed hostilities with Britain loomed, and Napoleon needed funds for his European wars. Without naval dominance, Louisiana could fall to the British anyway. To the Americans' astonishment, Napoleon decided to sell the entire territory. Livingston and Monroe had no authorization to purchase all of Louisiana. On April 30, 1803, they signed the deal anyway for $15 million, less than 3 cents an acre. The US Senate ratified the treaty on October 20, 1803. The official transfer was completed on December 20, 1803.

A Continental Nation Takes Shape

In seven months, the United States had nearly doubled in size. The purchase stretched from the Mississippi River to the Rocky Mountains, from the Gulf of Mexico to the Canadian border. It eventually formed all or part of 15 American states. The western boundary of the country, which had been the Mississippi River since the Treaty of Paris, now reached the Rockies.

A question remained about West Florida, not resolved until the Adams-Onís Treaty of 1819 and final transfer in 1821. Jefferson wasted no time. On May 14, 1804, just five months after the transfer, he sent Meriwether Lewis and William Clark west from Illinois on an expedition to the Pacific Ocean. That same year, the Supreme Court would also reshape American government, as we cover in our episode on Marbury v. Madison and judicial review.