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  • Writer's pictureNorfolk Towne Assembly

America’s Unplanned Expansion – The Louisiana Purchase

In 1803 the United States unexpectedly added the largest increase in land area in its history. How did this come about? Why was the young United States interested in acquiring territory in the French holdings in North America? To understand this, we need to look at the origins and history of this area.


By 1750, due to their early explorations in the 17th Century, the French controlled not only Canada, but also the Mississippi River Valley and almost all the lands drained by its tributaries. However, hostility between the French and British led to the beginning of the Seven Years' War in Europe, and in North America as the French and Indian War. After some early victories from 1754 to 1757, the French suffered several disastrous defeats in Canada from 1758 to 1760, culminating in the surrender of the capital city Quebec. The Treaty of Paris, signed on 10 February 1763, formalized the removal of the French from North America. Canada and the east bank of the Mississippi were handed over to Great Britain. However, the French colony of Louisiana was ceded to the Spanish Empire. This included the City of New Orleans and the lands on the west bank of the river. During the American Revolution, this Spanish Colony became an important source of weapons and other support for American forces fighting the British. Additionally, when the French entered the war, the Spanish (who by this time were allied with the French) carried out a military campaign capturing British forts along the Mississippi River and the Gulf Coast.

As Americans moved west across the Appalachian Mountain chain, the Mississippi River and access to the port at New Orleans became critical to settlers west of the mountains for moving their products to world markets and for access to imports from around the world. The rapid growth of Kentucky and of the American settlements at the Illinois, and shipments of American corn down the Mississippi, combined with what the Spanish saw as the ambition of the Americans, made them a menace to Spain’s possessions. After some consideration, Spain developed a remedy; strangle the American West by closing its only commercial outlet, the Mississippi, arresting any American caught using the river, and confiscating their property. Eventually, Pinckney's Treaty, also commonly known as the Treaty of San Lorenzo or the Treaty of Madrid, signed in San Lorenzo de El Escorial on October 27, 1795, declared intentions of friendship between the United States and Spain. It defined the border between the United States, Spanish Florida, and Spanish Louisiana, and guaranteed the United States navigation rights on the Mississippi River.

This solution, however, did not last long. In 1796, Spain joined the French in an alliance against England. Colonies were viewed as valuable assets; the loss of the sugar-producing colonies of Haiti (Saint-Domingue), Martinique, and Guadeloupe between 1791 and 1794 had a huge impact on French business. Restoring them was a priority, and when Napoleon seized power in November 1799, he and his deputy Charles Talleyrand stressed the need for French expansion overseas. The Third Treaty of San Ildefonso was a secret agreement signed on 1 October 1800 between the Spanish Empire and the French Republic by which Spain agreed in principle to exchange its North American colony of Louisiana for territories in Tuscany. The terms were later confirmed by the March 1801 Treaty of Aranjuez.

Americans transporting goods down the Mississippi to New Orleans
Americans transporting goods down the Mississippi to New Orleans

Jefferson worries about French intentions

Fear of an eventual French invasion spread across America when, in 1801, Napoleon’s intentions to reestablish a colonial empire in North America and the Caribbean became obvious. Southerners feared that Napoleon would free all the slaves in Louisiana, which could trigger slave uprisings elsewhere while those living in the territories west of the Appalachians feared that the French would once again close the Mississippi and economically “strangle” the growth of the young United States. By 1802 New Orleans had been transformed into one of the busiest ports in North America, overseeing in that one year more than $5 million in goods. Foreign trade had grown rapidly. As of 1794 only 31 oceangoing vessels had cleared port at New Orleans; but the number grew to 78 in 1799, slightly more than 200 in 1801, and 265 in 1802, with most of them sailing for ports outside North America. Exports in 1802 included 2 million pounds of cotton; almost 2.5 million pounds of sugar; 167,000 pounds of lead from Upper Louisiana and the Illinois Country; more than 200,000 pounds of hides and furs–including deer, beaver, otter, bear, and fox; more than 80,000 pounds of indigo; 50,000 barrels of flour; 2,000 hogsheads of tobacco; 3,000 barrels of salted beef and pork, and 800 hogsheads of molasses.

The chief obstacle to Napoleon's designs for a North American empire lay in Saint Domingue, France's most valued trading resource in the Caribbean and the gateway to the Gulf approaches to Louisiana. In 1791 the island's slaves, inspired by the French revolution, revolted under the leadership of François-Dominique Toussaint Louverture. Born a slave in Saint-Domingue, he won his freedom and became a French general. He had fended off incursions from other European powers but had also begun to consolidate power for himself on the island. Before the French Revolution, France had derived enormous wealth from St. Domingue, and Napoleon wanted its revenues and productivity for France restored.

Because Napoleon did not have enough troops to reconquer Saint Domingue and occupy Louisiana simultaneously, he decided first to subdue the rebel slaves and reestablish French authority on Saint Domingue. In the fall and winter of 1801, he dispatched to Saint Domingue an army of 20,000 men under his brother-in-law, General Charles Victor Emmanuel Leclerc. Napoleon also assembled an expedition at a Dutch port in the winter of 1802-03 for reinforcing Leclerc's army and, with Saint Domingue as it base of operations, to take possession of Louisiana.

Toussaint Louverture
Toussaint Louverture

Alarmed over the French actions and fears of its intention to re-establish an empire in North America, Jefferson declared neutrality in relation to the Caribbean, refusing credit and other help to the French, but allowed war contraband to get through to the rebels to prevent France from regaining control of the colony.

In 1804, after suffering massive losses in battle at the hands of the Hattian army, and losing thousands of men to yellow fever, the French capitulated and withdrew permanently from Saint-Domingue.

Negotiations for Purchase.

Jefferson and Secretary of State James Madison had hoped to fashion a foreign policy congenial to French interests. They disapproved of the slave uprising in Saint-Domingue and had intimated through diplomatic channels that the United States might help France in subduing L'Ouverture. They had also appointed the pro-French Robert R. Livingston as American minister to Paris.

Robert Livingston
Robert Livingston

By early 1802 events in Europe led Jefferson to reappraise and reformulate American relations with France, especially considering her intended occupation of the Mississippi River and the port of New Orleans. War between France and Great Britain was expected and Jefferson, who was perhaps America’s foremost geographic thinker, realized that if France claimed Louisiana, Great Britain would try to capture and occupy the region. In an April 18, 1802, letter to Minister Robert R. Livingston, Jefferson revealed that the prospect of potential war with France and the unpleasant consequence of an alliance with Great Britain completely reverses all the political relations of the U.S.

Over the course of several years President Thomas Jefferson prepared to handle an impending French presence in the Mississippi Valley and his administration’s first great diplomatic crisis. Jefferson was probably America’s foremost geographical thinker and a student of the American West. To head off the prospect of the British attacking New Orleans, in May 1802, Secretary of State Madison instructed Livingston to negotiate for the purchase of New Orleans and to learn whether the Spanish cession to France included East Florida and West Florida. If so, he was to negotiate a price for buying them, or at least the right of navigation and deposit on one of the rivers feeding into the Gulf.

James Monroe
James Monroe

By the end of 1802, negotiations with France were at a standstill and so, in January 1803 Jefferson nominated his friend and former Minister to France, James Monroe, as a special envoy to aid Livingston in persuading Napoleon to sell New Orleans. Monroe was an ideal choice, since he held the confidence of both the French government and, as a former governor of Virginia, the frontiersmen of the west. Jefferson authorized Monroe to offer $10 million for the Isle of Orleans and the Floridas. He also urged Monroe to hasten his departure, as "the moment in France is critical," noting Napoleon’s inability to quell the uprising in Saint Domingue prevented his forces from invading Louisiana. Secretary of State Madison’s official instructions to Livingston and Monroe show he hoped that France’s imminent war with Great Britain, among other circumstances, would lead her to abandon her interests in the West Indies rather than protect them at great expense. And, if an arrangement with France was not forthcoming, the American envoys were to open communications with the British government.

Events outside the control of either Livingston or Monroe forced Napoleon’s hand. After a year of ferocious fighting on Saint Domingue, the French army under Leclerc was depleted from the effects of guerrilla warfare and yellow fever. Napoleon’s fleet of reinforcements remained icebound at port in Europe. France’s impending war with Great Britain diverted resources towards the European continent, leaving Louisiana vulnerable to attacks from the superior British naval forces. Finally, Napoleon may have been convinced that the Americans themselves posed a threat to his possessions. For some time, he had been receiving reports of saber rattling among western Americans and in March 1803 Livingston gave him a copy of the Federalist motion calling for an invasion of New Orleans.

Charles Talleyrand
Charles Talleyrand

By April, Napoleon had decided to rid himself of the entire territory. This was disclosed to the American diplomats by his Minister of Foreign Affairs Charles Maurice de Talleyrand-Périgard. Reporting to Madison on the morning of April 11, an astonished Livingston wrote that:

"Mr. Talleyrand asked me this day, when pressing the subject, whether we wished to have the whole of Louisiana. I told him no, that our wishes extended only to New Orleans & the Floridas He said that if they gave New Orleans the rest would be of little value, & that he would wish to know ‘what we would give for the whole’."

The American representatives received the news with equal amounts of delight and hesitation, as they had no authorization to buy Louisiana in its entirety. However, rather than risk another change in Napoleon’s plans while awaiting communications with Washington, they decided to exceed their instructions and negotiate a purchase. Putting their mutual jealousies aside, the two American negotiators debated treaty drafts, one of which was prepared by Napoleon himself, with François de Barbé-Marbois, a career diplomat and French cabinet official, and negotiated a price over the last two weeks of April. An early draft treaty from Barbé-Marbois was rejected by Livingston and Monroe as being too indefinite and not clearly rendering title to West Florida. After several days of haggling and revisions they signed the treaty of cession and the two conventions attached to it on April 30.

The treaty consisted of 16 articles and 2 conventions, laying out 3 interdependent agreements.

1. France would cede Louisiana to the United States for 80 million francs at a fixed exchange rate of 5.3333 francs to the dollar (or $15 million).

2. The United States agreed to pay France $11,250,000 dollars in stock bearing 6 percent interest and assume $3,750,000 in debt claimed by American citizens against France for privations committed on the high seas.

3. France would also get favorable commercial privileges at New Orleans.

The treaty was not specific as to the exact boundaries of the purchase, perhaps because the French were not sure of them. The United States bought the entire western drainage basin of the Mississippi River–a region of ambiguous limits and uncertain proportions–as an outlet for the East in exchange for an amount of money that exceeded the total deposits of the federal treasury. When Livingston pressed the French on the issue of Louisiana’s borders, the French foreign minister replied:

"You have made a noble bargain for yourselves, and I suppose you will make most of it.”

News of the treaty reached the United States the last week of June 1803. Newspaper headlines ran the story several days before President Jefferson received official notification. As congressional debate over the Purchase neared, Jefferson was faced with the challenges of organizing this new territory and justifying its acquisition to the nation. Members of Congress complained that he had failed to abide by his earlier message and give them adequate details on the geography of the Louisiana territory and modern, accurate information, such as a precise delimitation of the region’s boundaries, its natural features, the people and their customs, and its potential commercial and political value.

First page of the report Jefferson sent to Congress
First page of the report Jefferson sent to Congress

Jefferson had already begun to remedy that gap in knowledge in the summer of 1803, when he drew up a list of 45 questions to distribute to individuals personally acquainted with Louisiana. The responses to Jefferson’s questions on the new territory were assembled and redacted under his direction and with benefit of his own extensive readings. On November 14, 1803, Jefferson presented Congress with An Account of Louisiana, a digest of all he knew on the subject. The document was an introduction to the territory’s geography, natural resources, government, laws, courts, commerce, taxes, and Native American inhabitants. Given Jefferson’s efforts during the summer of 1803 at defining Louisiana’s boundaries, it held relatively little information on that subject.

Obstacles potentially prevented the transfer of territory. The French constitution forbade the separation of French territory without legislative approval. Spain objected on the grounds that France had never completely fulfilled the terms of the Treaty of San Ildefonso, thereby nullifying French possession of Louisiana. Doubts arose over the legality of the purchase, for the United States Constitution had no wording on the acquisition of new territory. All problems, however, were soon resolved to the benefit of the United States. Napoleon simply acted without legislative authority and Spain was powerless to halt the retrocession.

Jefferson sent the treaty to the Senate on October 17. The New England Federalists at once raised heated protests, particularly with regard to its extra-constitutionality. The Senate Republican majority, however, approved the treaty on the evening of October 20 by a vote of 24 to 7. The House appropriated funds, which also supported the temporary occupation and government of Louisiana.

Transfer of Louisiana to the United States
Transfer of Louisiana to the United States

Louisiana’s inhabitants, primarily French in language, customs, and heritage, greeted the colony’s acquisition by the United States with mixed feelings of surprise, anger, and apathy. President Jefferson appointed William C. C. Claiborne, governor of the Mississippi Territory, and U.S. Army General James Wilkinson to receive the territory on behalf of the United States. On December 20 the French Governor Laussat met with the two American commissioners in the great hall of the Cabildo to sign the deed of cession transferring possession of Louisiana from France to the United States.

A dispute soon arose between Spain and the United States about the extent of Louisiana. The territory's boundaries had not been defined in the 1762 Treaty of Fontainebleau that ceded it from France to Spain, nor in the 1801 Third Treaty of San Ildefonso ceding it back to France, nor the 1803 Louisiana Purchase agreement ceding it to the United States. The U.S. claimed that Louisiana included the entire western part of the Mississippi River drainage basin to the crest of the Rocky Mountains and land extending to the Rio Grande and West Florida. Spain insisted that Louisiana included no more than the western bank of the Mississippi River and the cities of New Orleans and St. Louis.

Zebulon Pike, leader of the Pike Expedition
Zebulon Pike, leader of the Pike Expedition

Because the western boundary was contested at the time of the purchase, President Jefferson began to organize three missions to explore and map the new Territory. All three started from the Mississippi River. The Lewis and Clark Expedition (1804) traveled up the Missouri River; the Red River Expedition (1806) explored the Red River basin; the Pike Expedition (1806) also started up the Missouri but turned south to explore the Arkansas River watershed. The maps and journals of the explorers helped to define the boundaries during the negotiations leading to the Adams–Onís Treaty, which set the western boundary as follows:

“The Boundary Line between the two Countries, West of the Mississippi, shall begin on the Gulf of Mexico, at the mouth of the River Sabine in the Sea, continuing North, along the Western Bank of that River, to the 32d degree of Latitude; thence by a Line due North to the degree of Latitude, where it strikes the Rio Roxo of Nachitoches, or Red-River, then following the course of the Rio-Roxo Westward to the degree of Longitude, 100 West from London and 23 from Washington, then crossing the said Red-River, and running thence by a Line due North to the River Arkansas, thence, following the Course of the Southern bank of the Arkansas to its source in Latitude, 42. North and thence by that parallel of Latitude to the South-Sea [Pacific Ocean]. The whole being as laid down in Melishe's Map of the United States, published at Philadelphia, improved to the first of January 1818. But if the Source of the Arkansas River shall be found to fall North or South of Latitude 42, then the Line shall run from the said Source due South or North, as the case may be, till it meets the said Parallel of Latitude 42, and thence along the said Parallel to the South Sea.”

Thank you for joining us for today’s post on the story behind the Louisiana Purchase. We hope you found it interesting and gave you some perspective on how the United States came to control a sizable portion of the continent. Hopefully, it has encouraged you to learn more about this subject. Please join us again in two weeks for our next post when we will explore the history of one of the three expeditions of exploration that Jefferson sent into this unfamiliar territory to explore and determine the boundaries of the new purchase – the Zebulon Pike Expedition.

While you are here, on our website, we would also encourage you to join our blog community (Look for the button in the upper right-hand corner of this post). This will allow us to inform you when we post new articles. We also suggest that you return to our blog home page and sample some of our earlier articles on a wide variety of late-18th and early-19th century subjects; both military and civilian.

Finally, if you live in Virginia, Maryland, or North Carolina, we invite you to visit The Norfolk Towne Assembly’s home page to learn more about us, what we do, and how you can get involved in our historic dance, public education, and living history efforts.


Constitutional Rights Foundation. "Haiti's Slave Revolt and War for Independence." Bill of Rights in Action Winter 2020: 1-4.

Daut, Marlene L. "The Wrongful Death of Toussaint Louverture. " History Today 6 June 2020.

Library of Congress. Louisiana: European Explorations and the Louisiana Purchase. Special Report. Washington, D.C.: Library of Congress, 2014.

M., Slone W. "The World Aspects of the Louisiana Purchase." The American Historical Review Apr 1904: 507-521.

Potter, Lee Ann, Karen Needles and Marisa Wiliarat. "The Purchase of the Louisiana Territory." Social Education March 2003: 100-104.

Wilson, Gaye. "Jefferson's Big Deal: the Louisiana Purchase." Monticello Newsletter Spring 2003: 1-5.


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