The Louisiana Purchase took place in 1803, a major expansion in the history remembered during America250.
The United States acquired approximately 827,000 square miles of territory from France for $15 million. The purchase covered land west of the Mississippi River and expanded the nation dramatically, although the exact boundaries were later clarified through additional agreements.
President Thomas Jefferson authorized the transaction, which was negotiated by diplomats Robert R. Livingston and James Monroe with Napoleon Bonaparte’s government. The United States formally took possession in December 1803. The acquisition helped secure control of the Mississippi River and the port of New Orleans.
The purchase more than doubled the area of the United States. It also raised difficult questions about Indigenous sovereignty, slavery’s expansion, and the political status of the new territories—issues that shaped American history long after 1803.