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Louisiana Purchase Overview

Jun 20, 2025

Overview

This lecture explains the Louisiana Purchase of 1803, focusing on its background, negotiation, and significance in U.S. history.

Background: France in the New World

  • France explored and settled the Mississippi River valley and controlled vast American territory by the 18th century.
  • After the French and Indian War, France ceded Louisiana west of the Mississippi to Spain and transferred other territories to Great Britain.
  • Spain, then a declining power, made little effort to develop the Louisiana region it received.

Louisiana Territory Changes Hands

  • In 1801, Spain secretly agreed to return the Louisiana Territory to France.
  • Americans settling westward relied heavily on the Mississippi River and New Orleans port for trade.
  • U.S. leaders feared France, under Napoleon, would threaten American access to the Mississippi and Gulf of Mexico.
  • President Thomas Jefferson instructed U.S. diplomats to negotiate for the purchase of New Orleans.

Louisiana Purchase Negotiations

  • In 1802, American rights to store goods in New Orleans were revoked, alarming the U.S.
  • Jefferson sent James Monroe to join Robert Livingston in Paris to negotiate.
  • Due to military failures, a slave revolt in Haiti, looming war with Britain, and financial troubles, France offered to sell the entire Louisiana Territory.
  • The U.S. agreed to pay $11.25 million and assume $3.75 million in claims against France, buying 828,000 square miles.
  • The purchase treaty was signed in May 1803 and ratified later that year.

Legacy and Importance

  • The Louisiana Purchase doubled the size of the United States for less than three cents per acre.
  • It is regarded as one of Jefferson’s most significant achievements.
  • American expansion westward started immediately, with a territorial government formed in 1804.
  • Jefferson commissioned the Lewis and Clark Expedition to explore the new lands.
  • Louisiana became the 18th U.S. state in 1812, nine years after the purchase.

Key Terms & Definitions

  • Louisiana Purchase — 1803 acquisition of the Louisiana Territory from France, doubling the size of the U.S.
  • Mississippi River — Major waterway essential for trade and settlement in early U.S. history.
  • Napoleon Bonaparte — French leader who sold the Louisiana Territory to the United States.
  • Lewis and Clark Expedition — Exploration mission to map and study lands from the Louisiana Purchase.

Action Items / Next Steps

  • Review key dates: 1803 (purchase), 1804 (territorial government), 1812 (Louisiana statehood).
  • Study the impact of the purchase on westward expansion and U.S. development.