The United States completed the Louisiana Purchase in 1803, a major expansion associated with America250 history.
The agreement transferred approximately 828,000 square miles of territory from France to the United States. The land extended west of the Mississippi River toward the Rocky Mountains, although its exact boundaries were not immediately clear.
President Thomas Jefferson authorized the purchase from Napoleon Bonaparte’s government for 15 million dollars, including the assumption of certain claims. The treaty was signed in Paris on April 30, 1803, and the United States formally took possession later that year.
The purchase roughly doubled the size of the United States and strengthened control of the Mississippi River and the port of New Orleans. It also accelerated westward expansion, with profound and often devastating consequences for Native nations already living in the region.