What was the 1803 acquisition of a vast French territory by the United States called?

The 1803 acquisition of a vast French territory by the United States was called the Louisiana Purchase.

President Thomas Jefferson authorized James Monroe and Robert R. Livingston to negotiate with France for New Orleans and access to the Mississippi River. Instead, France offered the entire Louisiana Territory. The United States agreed to pay 60 million francs and assume 20 million dollars in claims by American citizens against France.

The treaty was signed in Paris on April 30, 1803, and the United States took formal possession later that year. The purchase covered roughly 828,000 square miles, although its boundaries were initially unclear. It extended American claims west of the Mississippi River and nearly doubled the country’s nominal size.

The territory included land that later became all or parts of 15 present-day states and two Canadian provinces. The deal strengthened American control of the Mississippi system and opened the way for later westward expansion. It also raised constitutional questions because the Constitution did not explicitly describe a presidential power to purchase territory.