The Louisiana Purchase was a land deal in 1803 in which the United States bought a huge territory from France. It stretched from the Mississippi River toward the Rocky Mountains and changed the future shape of the country. The purchase nearly doubled the size of the United States and opened vast new regions for farming, trade, settlement, and exploration.
It matters because it showed how one decision could reshape geography, politics, and the lives of millions of people.
Key Facts
- The Louisiana Purchase was completed in 1803 during the presidency of Thomas Jefferson.
- The United States bought the Louisiana Territory from France for about $15 million.
- Area purchased ≈ 828,000 square miles.
- Cost per square mile ≈ 18.12 per square mile.
- The purchase nearly doubled the land area of the United States at the time.
- The Lewis and Clark Expedition, 1804 to 1806, explored parts of the new territory and gathered information about geography, resources, and Indigenous nations.
Vocabulary
- Louisiana Purchase
- The 1803 agreement in which the United States bought the Louisiana Territory from France.
- Territory
- A large area of land controlled by a government but not always organized as states.
- Expansion
- The growth of a country or region in size, influence, or population.
- Treaty
- A formal agreement between governments or nations.
- Sovereignty
- The authority of a government to control land and make laws within it.
Common Mistakes to Avoid
- Thinking the Louisiana Purchase included only the modern state of Louisiana is wrong because the territory covered land that became all or part of many future states.
- Saying the United States bought the land from Spain is wrong because France sold the territory to the United States, although Spain had controlled it earlier.
- Assuming the purchase immediately created new states is wrong because the land first became U.S. territory and was later organized into states over time.
- Ignoring Indigenous nations is wrong because many Native peoples already lived in and governed parts of the region, so the purchase did not mean the land was empty.
Practice Questions
- 1 The United States paid about $15,000,000 for about 828,000 square miles. Estimate the cost per square mile.
- 2 If the United States had about 864,000 square miles before the purchase and gained about 828,000 square miles, what was its approximate total area after the purchase?
- 3 Explain why the phrase doubling a nation describes the Louisiana Purchase, and identify one reason the purchase was important for the future of the United States.