The United States paid France $15 million for the Louisiana Purchase in 1803. The agreement transferred a vast territory west of the Mississippi River to the United States.
President Thomas Jefferson authorized the purchase after negotiations with Napoleon Bonaparte’s government. The final amount included $11.25 million paid directly to France and $3.75 million in claims owed to American citizens, producing the commonly cited total of $15 million.
The purchase covered about 828,000 square miles, although its exact boundaries were initially uncertain. It more than doubled the area of the United States and helped lead to the Lewis and Clark expedition, which explored the newly acquired region.