Louisiana Purchase


The Louisiana Purchase (1803) from France resulted in the eventual transfer of about 828,000 square miles of land in North America to the United States. At a cost of about $15 million, the United States nearly doubled its territory and effectively secured control over the Mississippi River by acquiring the port of New Orleans and the vast watershed beyond the river. Beginning in the mid-sixteenth century the French established control of the territory running from the Great Lakes to the Gulf Coast, only to cede much of it to Spain after the Seven Years’ War (1756–1763). In 1784, Spain closed the Mississippi to American commerce until the Treaty of San Lorenzo (1795). Five years later, however, the territory reverted to France while remaining under Spanish administration. The new U.S. president, Thomas Jefferson, inaugurated in 1801, spent the next two years negotiating long-term access to the river. Jefferson worried that war in Europe might leave the British in control of Louisiana or even that American settlers might establish new nation-states in the Mississippi valley and negotiate their own treaty with the French. The crisis worsened in 1802 when the Spanish closed the river again; some in the opposition Federalist Party suggested the United States go to war. Then, in 1803, the French suddenly offered to sell imperial rights to all of Louisiana. Jefferson seized upon this unexpected opportunity, but worried that the U.S. Constitution did not allow such a deal. Still, he called Congress to an early session and laid the treaty before the Senate to ratify, which they did. The acquisition of so much territory eventually strained the union between North and South and helped to bring on the American Civil War (1861–1865). Unplanned and unexpected, the Louisiana Purchase presented the federal government and the American people with an array of new challenges and new opportunities.


La Salle Taking Possession of Louisiana

French claims to the Mississippi watershed and the central Gulf Coast dated to the late seventeenth and early eighteenth centuries when French explorers descended the Mississippi from the Great Lakes and French officials established Biloxi (1699), Mobile (1702), and New Orleans (1718). These new towns and their surrounding settlements grew slowly, but their place in French aspirations was immense. New Orleans was to be the southern counterpart to Quebec and Montreal, providing the same commercial and governmental functions for Louisiana—the whole of the Mississippi watershed—that those cities provided for New France—the whole of the St. Lawrence watershed. In the 1740s and 1750s, France began building new forts and trading posts hundreds of miles north of the Gulf of Mexico to strengthen the connections between its colonies and to secure its claims against the British colonies along the Atlantic Coast.

The growing French presence in what Virginians and Pennsylvanians viewed as their backcountry led to the outbreak of the French and Indian War (1754–1763), the North American theater of the Seven Years’ War (1756–1763). This first world war saw fighting in Europe and in outposts of the British and French empires in the Caribbean, India, and Africa. For the British, it soon became a war to settle the future of eastern North America. Their conquest of Quebec (1759) and Montreal (1760) broke the French hold over New France. In the treaties of Fontainebleu (1762) and Paris (1763), respectively, the French ceded New Orleans and Louisiana west of the Mississippi to their Spanish ally, which lost Florida to the British, and New France and Louisiana east of the river to the British. These cessions did not require the parties to define the boundaries of Louisiana along the Gulf Coast, as everything west of the Mississippi now belonged to Spain and everything east of the river, except what was called “the island of New Orleans,” now belonged to Great Britain.

Saint Louis Street in New Orleans

After the American Revolution (1775–1783), Spanish control over New Orleans and the lower Mississippi emerged as a vital issue for the first generation of American policymakers. Spain had recovered Florida from Great Britain during the Revolution, giving it control over the whole of the Gulf Coast. While the border between the United States and Spanish Florida remained unsettled, there was no question that Spain owned both banks of the Mississippi from the thirty-first parallel to the river’s mouth.

In 1784, Spain closed the river to American trade. American settlement across the Appalachians, which had begun after the French and Indian War and increased during the Revolution, was poised to increase even more with the return of peace. But new settlements in western Pennsylvania and Virginia, Ohio, Kentucky, and Tennessee could succeed only if they could use the region’s rivers to transport bulky agricultural surpluses to foreign markets; all of those rivers eventually fed into the Mississippi. Spain’s closure of the river seemed certain either to slow the westward movement of Americans, which was Spain’s intent, or to lead western settlers to break from the United States, establish their own nation-states, and negotiate separate access to the river.

Thomas Pinckney

For more than a decade, the United States tried to arrange terms with Spain, even as disunionist sentiment flared across the Appalachians. In 1795, the Treaty of San Lorenzo—also known as Pinckney’s Treaty, after the United States’ chief negotiator, Thomas Pinckney—resolved most of the outstanding issues. It defined the unsettled border, opening the river to American use, and fixed a “right of deposit” at New Orleans so produce brought downriver on flatboats could be warehoused until it was loaded onto ocean-going vessels.

Even as the United States had worked to secure its hold over the eastern part of the Mississippi watershed during the 1790s, revolutionary France had turned its attention to the western part, to Spanish Louisiana. In October 1800, French pressure on Spain produced an agreement. The Third Treaty of San Ildefonso restored Louisiana—defined only as what had been ceded to Spain in 1762—to France, but left it temporarily under Spanish administration.

The Mississippi Crisis

Thomas Jefferson

Rumors of Louisiana’s return to French control reached the United States shortly after the inauguration of Thomas Jefferson as the third U.S. president on March 4, 1801. Jefferson, Secretary of State James Madison, and their diplomats in Europe immediately saw the transfer of the province from a relatively weak Spain to a much stronger France as reviving the threat to the union of the eastern and western parts of the United States that had been quieted by the Treaty of San Lorenzo.

The danger did not arise from France’s control over the great mass of Louisiana beyond the Mississippi, but rather from its control over the miniscule portion of Louisiana east of the river—the island of New Orleans and anything else along the Gulf Coast that had been included in the retrocession. With New Orleans in his hands, Napoleon Bonaparte, then First Consul of the French Republic, could use control over western commerce to pry western settlers from the United States, either expanding his own empire in the middle of the North American continent or creating a second American nation-state whose interests would inevitably clash with those of the one on the Atlantic Coast.

The Mississippi Crisis raged for more than two years until its unexpected resolution in the spring of 1803. Throughout, Jefferson and his diplomats shaped policies that they hoped would secure western trade and, thus, the federal union. Weighing among the European options, they decided that, from this perspective, Louisiana was safest in Spanish hands and most dangerous under British control. Initially, they hoped simply to convince Napoleon to revoke the transfer, returning Louisiana to Spain. When that plan failed, they sought to convince Napoleon to accept the terms of the Treaty of San Lorenzo, accommodating western commerce in the same way that Spain had in 1795. At the same time, Jefferson and Madison began trying to arrange a land purchase.

What they wanted to buy, however, was not the whole of Louisiana. Instead, they set their eyes on territory east of the river—the island of New Orleans, West Florida (the Gulf Coast from the Mississippi east to the Pearl or Perdido river), and East Florida (modern Florida). Not knowing how much of this territory had been included in the still-secret Treaty of San Ildefonso, they directed diplomats Charles Pinckney, in Madrid, and Robert R. Livingston, in Paris, to broach a purchase. What Pinckney and Livingston discovered was that their hosts did not want to discuss the retrocession, did not seem certain whether any territory east of the river, other than the island of New Orleans, had been included in the treaty, and did not want to sell in any case.

Haitian Revolution

Even though their diplomatic efforts had failed so far, Jefferson and Madison believed, eighteen months into the crisis, that time was on their side. Spanish officials continued to administer Louisiana and to respect the terms of the Treaty of San Lorenzo. Differences between France and Spain over what was included in their treaty might result in its revocation. Peace between France and Great Britain, though recently restored, seemed fragile; a renewed war would forestall France’s return to Louisiana in force. And France’s difficulties suppressing the nearly decade-old Haitian Revolution (1791–1804) prevented it from committing much of its army or navy to its new mainland colony. Delay, whatever its source, seemed to favor the United States, allowing it time to develop stronger bonds between its eastern and western regions and to increase its population beyond the Appalachians. This region would be the likely source of the militiamen and volunteers who could descend upon New Orleans if military measures became necessary.

Plano de la Cuidad de Nueva — Orleans

Late in 1802, however, the crisis suddenly grew more intense when a Spanish official in New Orleans suspended the right of deposit that had made western trade down the Mississippi possible. New ideas about how to resolve the crisis emerged inside and outside the Jefferson administration. Some westerners demanded immediate American military action to seize New Orleans. It seemed clear that if the federal government did not take effective steps, then westerners might raise their own force and act for themselves. Federalists, who opposed Jefferson’s Democratic-Republican Party, also argued for quick military action, making their case in both Congress and the press. Writing in a New York newspaper, the Federalist leader Alexander Hamilton urged the government to seize New Orleans and everything east of the river immediately and then negotiate. Instead, Jefferson and Madison decided to send to France a special envoy, James Monroe, to join the American minister there, Robert Livingston, in seeking a peaceful settlement.

James Monroe

Madison’s instructions for Monroe and Livingston provided a range of options for resolving the crisis, most of which involved the acquisition of new territory. Even the most expansive of these options, however, included nothing beyond the Mississippi. Ideally, Monroe and Livingston would purchase everything east of the river—the island of New Orleans and the two Floridas—with a boundary running down the river to the Gulf—for as much as $6 million. But other acceptable outcomes included purchasing West Florida and New Orleans, or West Florida alone, or New Orleans alone, or even land along the banks of the Mississippi where the United States could build its own port city as a substitute for New Orleans.

Any of those options would have provided a long-term solution to the crisis. But Livingston and Monroe were also empowered to effect a short-term solution, one that might postpone military action until a time when the Union was stronger and the American population in the West larger. Even a formal assurance by France of the rights of trade and deposit and the addition of the rights to own land and to have an official agent in New Orleans would have served those purposes. If Monroe and Livingston could not achieve at least those protections, Jefferson and Madison believed, then an immediate recourse to war would become necessary.

Negotiating the Purchase

Portrait de François

In Paris, Livingston had been trying to open negotiations to resolve the crisis for months before learning that Monroe was to join him. He had explored both the formal channel, through the French foreign minister, Charles-Maurice de Talleyrand Périgord, and informal channels, such as through Napoleon’s brother, Joseph Bonaparte. On April 12, 1803, the day of Monroe’s arrival in Paris, Livingston looked up from his dinner table and spotted the treasury minister, François Barbé-Marbois, walking in his garden. Later that evening, the two met and Barbé-Marbois offered to sell the whole of Louisiana, everything that had been recovered from Spain, to the United States for 100 million livres (about $19 million).

For years, Napoleon had looked to Louisiana as the centerpiece of a revived French empire in North America. His sudden and unexpected decision to sell it to the United States arose from various developments. The continuing setbacks in Saint Domingue (Haiti) weighed against keeping Louisiana, which had been expected to provide cheap foodstuffs and other supplies for the valuable, sugar-producing colony. The growing evidence of American concern—including not only the Monroe mission, but also the calls for military action in western and Federalist newspapers—may have suggested that New Orleans, at least, was likely to be lost to France without recompense.

The Emperor Napoleon in His Study at the Tuileries

The increasing likelihood of renewed war with Great Britain seems to have been the most important factor, however. War would postpone, if not end, Napoleon’s dreams of a North American empire, as the British would not allow the French to establish themselves in Louisiana. In contrast, selling the province to the United States would keep it from falling into British hands and provide much-needed gold on the eve of the war. It might also dispose the United States to remain neutral, securing a source of vital supplies for France’s Caribbean colonies.

On the night of Barbé-Marbois’s proposal, Livingston decided that he and Monroe would accept the offer, but try to lower the price. Over the next two weeks, the three men worked toward an agreement on price and terms with an understanding that their task would become far more difficult if it were not completed before war between France and Great Britain resumed. They settled on 80 million livres ($15 million), a quarter of which would be used to pay the claims of American merchants against France.

Signed on April 30, 1803, the hastily drawn treaty departed from the administration’s intentions in various particulars, including how the United States was to pay France, how American merchants were to be compensated for their claims, and what was to be said about those who lived in any acquired territory. Most importantly, though, it required the United States to pay two-and-a-half times what Monroe and Livingston had been authorized to spend to buy an immense territory that they had never been instructed to buy. And it left entirely undefined the boundaries of the purchase.


Official news of the Louisiana Purchase reached Jefferson on July 3, 1803. Even without knowing its precise terms, he immediately recognized that it would resolve the two-year-old Mississippi Crisis by ending foreign interference with western commerce. And he quickly saw that owning both banks of the Mississippi from the mouth to its source would prevent future wars with whatever European power might have acquired the western bank.

But Jefferson also understood that the Louisiana Purchase presented new problems. For one thing, he believed that the purchase to be unconstitutional. Jefferson and his supporters were strict constructionists with regard to the U.S. Constitution; they viewed it as a grant of limited powers to the federal government and insisted that it be interpreted narrowly. There was no clause in the Constitution that gave the federal government the power to acquire new land and to promise that it would be added to the existing Union. Jefferson also worried that settling the new territory too quickly might disrupt the Union by leading to the establishment of new states with interests at odds with those of existing states.

Wilson Cary Nicholas

In response to both of these concerns, Jefferson drafted a constitutional amendment, explaining to Senator Wilson Cary Nicholas, of Virginia, “I had rather ask an enlargement of power from the nation, where it is found necessary, than to assume it by a construction which would make our powers boundless.” The amendment would have legalized the purchase, at least retroactively, while closing the vast majority of Louisiana—all land north of the thirty-first or thirty-second parallel—to American settlement. Jefferson’s idea was to use it instead as a home for American Indians living east of the Mississippi, whose lands would then become available for American farmers and planters. Slowing the pace of expansion in this manner, Jefferson believed, would allow more time for the bonds between East and West to strengthen while preventing the emergence of any new American nation-states in the Mississippi valley. Over the next few months, however, the president failed to win support for the amendment in either his cabinet or Congress.


Reaction to the Louisiana Purchase across the United States showed a similar blend of relief, even hope, and concern, even fear. Most Republican newspapers celebrated the purchase as a triumph of Jeffersonian statecraft and a guarantee of future prosperity and peace. Privately, however, many eastern Republicans shared the president’s fear that too-rapid expansion beyond the Mississippi could endanger the still-young republic and the still-fragile union.

Federalists attacked the purchase both publicly and privately. They condemned the administration’s mishandling of the recent crisis and attributed the successful outcome to sheer luck. They criticized the expense, arguing that what was truly valuable—the island of New Orleans and Spanish West Florida—could have been acquired for much less. But they also argued that expansion west of the Mississippi was certain to result in the creation of many hostile nations in North America. In his first published response to the news of the purchase, Hamilton even urged Jefferson to negotiate a new treaty with Spain to exchange the whole of Louisiana west of the Mississippi for East and West Florida. Some New York and New England Federalists began discussing their region’s secession from a union that was becoming too large and too different from the one they had helped form barely fifteen years earlier.


Hoisting American Colors

The U.S. Senate ratified the Louisiana Purchase on October 20, 1803, and soon after many of the ramifications of the new acquisition became apparent. Even before the United States took formal possession of Louisiana on December 20, 1803, three of the biggest questions raised by the purchase had become clear: What were its boundaries? How would its people be governed? And would slavery be permitted to remain in those parts of Louisiana where it already existed or to spread into those parts where it did not?

Soon after learning of the purchase, Jefferson began trying to determine its boundaries using old treaties, maps, and histories. He decided that the United States had a weak claim to land along the Gulf Coast east of the Mississippi and a stronger claim along the coast west of the river, possibly including Spanish Texas. With France uninterested in defining Louisiana’s boundaries, Jefferson and Madison sought negotiations with Spain to exchange some of these western claims for eastern territory. But Spain’s involvement in Europe’s wars and its insistence on the purchase’s illegitimacy under the terms of its treaty with France blocked any progress until 1819.

In the interim, the United States took advantage of Spain’s European troubles to seize control of West Florida. In 1818, the United States and Great Britain effectively defined the northern limits of Louisiana by agreeing to a border at the forty-ninth parallel from the Lake of the Woods (in present-day Minnesota and the Manitoba and Ontario provinces of Canada) to the Rocky Mountains. The next year, in the Adams-Onís (or Transcontinental) Treaty, the United States and Spain resolved all of their border issues without ever fixing what had been included in the Louisiana Purchase. The United States abandoned its claims to Texas and agreed to pay up to $5 million to cover Spanish obligations to American merchants. In exchange, it received all Spanish territories east of the Mississippi and a border with Spanish possessions in the West that extended from the Gulf of Mexico to the Pacific Ocean.

Early Information About Louisiana Territory

The U.S. government also struggled with how to govern this new territory. Officials divided the land into two territories: Louisiana, north of the thirty-third parallel was immense but lightly populated, at least by people of European or African origin. Orleans (i.e., the present-day state of Louisiana), south of the parallel, was small but heavily populated, and it posed the greater problem. Peopled by a heterogeneous mix of Europeans, Africans, and American Indians, it seemed unprepared, at least in the thinking of most Americans, for even limited self-government, the first stage of the territorial system. But the terms of the purchase obligated the United States to incorporate Louisianans as equal citizens as soon as possible, and the size of its population should have placed it immediately in the second stage of the territorial system, with the third and final stage—statehood—just a few years away.

Over the winter of 1803–1804, Jefferson and Congress crafted a governing ordinance for the Orleans Territory that would have limited local self-governance and delayed statehood. Almost immediately, Louisianans demanded more local autonomy and argued successfully on behalf of their French legal system. A new ordinance was adopted in 1805, but these tensions were not fully resolved until the Orleans Territory entered the union as the state of Louisiana in 1812.

The most intractable, and ultimately divisive, problem raised by the Louisiana Purchase concerned slavery. Urban and agricultural slaves made up a significant portion of the population of the Orleans Territory. Jefferson and Congress never considered ending slavery there, but they did prohibit the importation of new slaves except when brought with owners moving from other states. Local opposition soon removed even this limitation, with the Orleans Territory quickly emerging as a major purchaser of slaves both from within the United States and, before the international slave trade was abolished in 1808, from Africa and the Caribbean.

Speech of Mr. Tucker

In the much larger Louisiana Territory, slaves were relatively rare at the time of the purchase. Whether plantation agriculture and the slaves that made it profitable would expand into those parts of the purchase where they had not been entrenched in 1803 did not immediately emerge as an important question. In 1819, however, this issue nearly destroyed the Union when Missouri became the second territory beyond the Mississippi to apply for statehood; the Missouri Compromise (1820) admitted Missouri as a slave state, but drew a line across the purchase that would have allowed for just one additional slave state, Arkansas. This compromise held for more than three decades. Then, between 1854 and 1861, efforts to allow slavery in Kansas, another part of the Louisiana Purchase, resulted in bloody conflicts, destroyed the existing political party system, and played a crucial role in bringing about the American Civil War.

Robert Cavelier sieur de La Salle explores the Mississippi River from the Great Lakes to the Gulf of Mexico, establishing a French claim to Louisiana.
Jean Baptiste Lemoyne sieur de Bienville founds New Orleans at the site of a Native American village, ninety miles above the Gulf on the east bank of the Mississippi.
Fighting between Virginia militia and French soldiers begins at Fort Duquesne at the Forks of the Ohio River.
France transfers the island of New Orleans and all of Louisiana west of the Mississippi to Spain in the Treaty of Fontainebleu.
France cedes Louisiana east of the Mississippi, and nearly all of its Canadian possessions, to Great Britain in the Treaty of Paris.
September 3, 1783
The Treaty of Paris is signed in Paris, France, by Benjamin Franklin, John Adams, John Jay, and David Hartley. In the document, Britain formally recognizes American independence and cedes to America all lands south of the Great Lakes and east of the Mississippi River except for the Florida colonies.
Spain closes the Mississippi River to American trade.
October 27, 1795
After years of intermittent diplomacy, the United States and Spain sign the Treaty of San Lorenzo, opening the Mississippi River to American trade and establishing a right of deposit at New Orleans.
October 1, 1800
Spain returns Louisiana to France in the Treaty of San Ildefonso.
March 4, 1801
Thomas Jefferson is inaugurated as the third president of the United States.
May 25, 1801
The first reliable news of the retrocession of Louisiana reaches the Jefferson administration in a letter from Rufus King, the American minister to Great Britain.
October 16, 1802
Juan Ventura Morales, the intendant at New Orleans, suspends the American right of deposit at New Orleans.
January 11, 1803
Thomas Jefferson asks Congress to send James Monroe on a special mission to France and Spain.
January 18, 1803
President Thomas Jefferson sends a secret communication to Congress to request funding for an expedition to explore the North American West. Congress allocates $2,500 for the project.
April 12, 1803
James Monroe arrives in Paris, where the French minister of the treasury, François Barbé-Marbois, offers to sell the whole of Louisiana.
April 30, 1803
James Monroe, Robert R. Livingston, and François Barbé-Marbois sign the Louisiana Purchase.
July 3, 1803
Official news of the Louisiana Purchase reaches Thomas Jefferson in Washington, D.C.
July 5, 1803
Thomas Jefferson drafts a constitutional amendment to cover the Louisiana Purchase and to forestall settlement beyond the Mississippi River for the present.
October 20, 1803
The Louisiana Purchase treaty is ratified by the U.S. Senate, 24 to 7.
December 20, 1803
Territorial governor William C. C. Claiborne and General James Wilkinson formally receive Louisiana from French officials at New Orleans.
March 10, 1804
Another formal transfer of the Louisiana province is held in Saint Louis; others follow at New Madrid and Natchitoches.
March 26, 1804
"An Act erecting Louisiana into two territories, and providing for the temporary government thereof" is signed into law. It creates the Louisiana and Orleans territories.
April 30, 1812
The Orleans Territory enters the union as the state of Louisiana.
The United States and Great Britain fix the northern border of the Louisiana Purchase at the 49th parallel from the Lake of the Woods to the Rocky Mountains.
The United States and Spain resolve the dispute over the uncertain eastern and western boundaries of the Louisiana Purchase in the Adams-Onís (or Transcontinental) Treaty.
A bid for statehood by Missouri sparks a two-year crisis over the spread of slavery into the Louisiana Purchase. The Missouri Compromise resolves the crisis.
The question over whether slavery would be permitted in Kansas leads to local violence, destroys Whig Party, produces Republican Party, and helps to bring about the Civil War.
  • Brown, Everett S. The Constitutional History of the Louisiana Purchase, 1803–1812. Berkeley: University of California Press, 1920.
  • Kastor, Peter J. The Nation’s Crucible: The Louisiana Purchase and the Creation of America. New Haven, Connecticut: Yale University Press, 2004.
  • Kastor, Peter J., and François Weil, eds. Empires of the Imagination: Transatlantic Histories of the Louisiana Purchase. Charlottesville: University of Virginia Press, 2009.
  • Kukla, Jon. A Wilderness So Immense: The Louisiana Purchase and the Destiny of America. New York: Alfred A. Knopf, 2003.
  • Lewis, James E., Jr. The Louisiana Purchase: Jefferson’s Noble Bargain? Charlottesville, Virginia: Thomas Jefferson Foundation, 2003.
  • Rodriguez, Junius P., ed. The Louisiana Purchase: A Historical and Geographical Encyclopedia. Santa Barbara, California: ABC-Clio, 2002.
APA Citation:
Lewis, James. Louisiana Purchase. (2020, December 07). In Encyclopedia Virginia. https://encyclopediavirginia.org/entries/louisiana-purchase.
MLA Citation:
Lewis, James. "Louisiana Purchase" Encyclopedia Virginia. Virginia Humanities, (07 Dec. 2020). Web. 19 Jun. 2024
Last updated: 2020, December 14
  • This field is for validation purposes and should be left unchanged.