What territory did the United States buy from France through the Louisiana Purchase Treaty of 1803?

The United States bought the Louisiana Territory from France through the Louisiana Purchase Treaty of 1803.

The treaty was signed in Paris on April 30, 1803, by Robert Livingston, James Monroe, and François Barbé-Marbois. The United States agreed to pay $15 million, including assumptions of certain claims by American citizens against France. The purchase more than doubled the size of the country.

The territory stretched from the Mississippi River toward the Rocky Mountains and from the Gulf of Mexico northward. Its boundaries were not perfectly defined at the time, which led to later negotiations with Spain and Britain. The purchase also secured control of New Orleans and the Mississippi River system, both vital to American trade.

The name can cause confusion because modern Louisiana is only one part of the historic purchase. The acquired region eventually contributed land to all or parts of 15 present-day states. The United States formally took possession in December 1803, after France transferred the territory at New Orleans.