The Purchase and Exploration of Louisiana: Overview

As the frontier pushed to the west by the end of the eighteenth century, use of the Mississippi River to transport goods became an important issue for the United States. France ceded Louisiana to Spain in 1762. In the 1790s, Spaniards closed the Mississippi to all American traffic, causing internal American trouble. In 1800 Napoleon, however, succeeded in once more gaining ownership of Louisiana.

This transfer of Louisiana to France troubled President Thomas Jefferson. Not strong enough to fight Napoleon’s armies if such should become the need, Jefferson, a Francophile, saw the possibility of having to ally the United States with England, hoping that her navy could protect American interests against France. The solution?  Buy New Orleans which controlled the mouth of the Mississippi River from France. U.S. Minister to France Robert Livingston met with French Foreign Minister Talleyrand, offering to purchase New Orleans to give the United States control of the mouth of the Mississippi. Talleyrand’s response startled Livingston:  “What will you give us for the entire Louisiana?” Livingston stalled for time but did offer $4 million. “Too low,” was Talleyrand’s reply.

Jefferson had no idea that Napoleon was interested in selling the whole of Louisiana—a purchase that would double the size of the United States. In 1803 the president sent James Monroe to Paris to assist Livingston in negotiations. Napoleon, who was on the verge of war with England, feared that England might take Louisiana. That fear lay behind his desire to cede the territory to the United States. Haggling over the price took seven days. The United States paid 50 million francs, ($11,250,000) for the vast Louisiana country. Paying off American debts owed to France raised the sum to $15 million. The United States had acquired the right to govern and tax 529,911,680 acres of territory by signing the treaty of cession in Paris on April 30, 1803.

Jefferson submitted the treaty to the senate for approval. The Federalists violently opposed the treaty on the grounds that it was unconstitutional. Jefferson more than likely agreed but said nothing. The treaty was ratified on October 20, 1803.

The President had already decided to explore the lands west of the Mississippi—the territory of the purchase—and beyond it to the “Western Ocean.” His interest reflected his concern for the future of the nation and his insatiable inquiring scientific mind. The Lewis and Clark Expedition, the Corps of Discovery, was Jefferson’s logical first step in the Louisiana process.

Jefferson’s instructions to William Clark and Meriwether Lewis, the expedition leaders, were clear:  To explore the Missouri River and its tributaries, hoping to find a northern route to the Pacific, to gather all possible information about the Indian tribes and their relationships with each other, to establish friendly relations with the Indians and promote peace among them, and to record as much scientific data as possible.

The story of the expedition is by now familiar to most students. In 1804, the Corps traveled as far up the Missouri River as the Mandan and Hidatsa villages where they spent the winter of 1804-1805. It crossed the uncharted land between the Mandan and Hidatsa villages and the Pacific Ocean during 1805. They wintered at Fork Clatsop during the winter of 1805-1806 and returned to St. Louis on September 23, 1806, two years and four months after its departure. This was an unbelievable accomplishment with the loss of only one life.

Was the Lewis and Clark Expedition a success? Not until 1814 were the Corps’ findings published for the nation to study. Lewis’s death and Clark’s involvement in other matters caused the delay. The expedition clearly succeeded in establishing a solid scientific knowledge about the West, in drawing amazingly accurate maps and in its ethnographic descriptions of the many Indian tribes. By going beyond the confines of the Louisiana Purchase territory, it gave the United States a claim to the Pacific Northwest—“Oregon country.” The expedition failed, however, to create peace among those Indian tribes that traditionally had been at odds.

In the end, the Lewis and Clark expedition opened the West to American occupation and promoted the rapid westward movement of the fur trade frontier.


By Dr. D. Jerome Tweton


Originally published as The North Star Dakotan student newspaper, written by Dr. D. Jerome Tweton and supported by the North Dakota Humanities Council.

Subject Matter

Social Studies

North Star Dakotan:

Journals and Art Work: The Indian People, The Trade, and The Land

The Indian People

The Purchase and Exploration of Louisiana

The Fur Trade

Dakota Territory

The Military Frontier

The Reservation System

George Armstrong Custer and the Battle of the Little Bighorn

The Great Dakota Boom, 1878-1890

Reservation Troubles, 1886-1890

The Making of a State and a Constitution

The North Dakota Economy, 1890-1915

Life on the Indian Reservations

The North Dakota National Guard and the Philippines

North Dakota, The Great War and After

The Nonpartisan League's Rise to Power

The Nonpartisan League in Power

The Nonpartisan League's Decline

The 1920s

1930s: North Dakota's Economic and Political Climate

The New Deal in North Dakota

The Road to World War II

North Dakota and American Society

North Dakota Optimism and Economic Developments

North Dakota and Political Change

Related Media

  1. Jefferson on Lewis and Clark: Part 1
    Video: In this clip Mr. Jefferson reflects on his life and the Lewis and Clark Expedition.
  2. Jefferson on Lewis and Clark: Part 2
    Video: In this clip Mr. Jefferson answers an audience question about his plans for the West.
  3. Jefferson on Lewis and Clark: Part 3
    Video: In this clip President Jefferson answers audience questions about the Lewis and Clark expedition and what it accomplished..
  4. Jefferson on Lewis and Clark: Part 4
    Video: In this clip Mr. Jefferson answers an audience member's question about covering the costs of the Louisiana Purchase.
  5. Lewis and Clark's North Dakota: Jefferson's Vision
    Video: Thomas Jefferson had many purposes in mind when he commissioned the Lewis and Clark Expedition.

Related Links

“A Vast and Open Plain”: The Writings of the Lewis and Clark Expedition in North Dakota, 1804-1806, ed. and with an introduction by Clay S. Jenkinson, State Historical Society of North Dakota, 2003. Discovering Lewis and Clark, a web site sponsored by the Lewis and Clark Fort Mandan Foundation in Washburn, North Dakota, offers a well-researched and beautifully illustrated history of the Lewis and Clark Expedition. Highly recommended for teachers, students, and the general public. Artist Michael Haynes has created countless paintings of the Lewis and Clark Expedition in rich, vivid color and with scrupulous attention to historical detail.