The Louisiana Purchase was the 1803 land deal that nearly doubled the size of the United States.
The United States bought the Louisiana Territory from France for $15 million. President Thomas Jefferson had initially wanted access to New Orleans and the Mississippi River, but French negotiators offered the much larger territory. The agreement was signed on April 30, 1803, and the United States took possession later that year.
The purchase covered about 828,000 square miles west of the Mississippi River. Its boundaries were disputed and the territory included land that later became parts of 15 U.S. states and two Canadian provinces. The transaction extended U.S. claims toward the Rocky Mountains and created new opportunities for westward expansion.
The Louisiana Purchase is sometimes confused with the Alaska Purchase, which occurred in 1867. Alaska was bought from Russia for $7.2 million. The earlier Louisiana deal was negotiated with France under Napoleon Bonaparte’s government and remains one of the largest territorial acquisitions in U.S. history.