What was the 1803 U.S. acquisition from France called?

The 1803 U.S. acquisition from France was called the Louisiana Purchase.

President Thomas Jefferson authorized negotiations to secure New Orleans and protect American access to the Mississippi River. French representatives unexpectedly offered the entire Louisiana Territory, and U.S. negotiators Robert R. Livingston and James Monroe agreed to purchase it from the French First Republic.

The United States paid approximately $15 million, including the assumption of certain claims against France. The territory covered about 828,000 square miles and extended U.S. control west of the Mississippi River. It nearly doubled the country’s nominal size and included land that later became part of fifteen U.S. states and portions of two Canadian provinces.

The purchase raised constitutional questions because the Constitution did not explicitly describe a power to acquire foreign territory. Jefferson nevertheless supported the treaty, and the Senate ratified it in 1803. The deal is different from the 1867 Alaska Purchase, which transferred Alaska from Russia to the United States.