Which 1803 land deal nearly doubled the United States, a later milestone in America250 history?

The Louisiana Purchase was the 1803 land deal that nearly doubled the United States, a later milestone in America250 history.

The United States acquired the Louisiana territory from France in an agreement signed on April 30, 1803. President Thomas Jefferson had initially sought only New Orleans and access to the Mississippi River, but France offered the entire territory for $15 million.

The purchase transferred about 828,000 square miles to the United States, extending national claims west of the Mississippi River. It included land that later became all or part of 15 present-day U.S. states and two Canadian provinces.

The acquisition raised constitutional and political questions because the Constitution did not expressly describe a power to buy territory. Jefferson nevertheless supported it, and the Senate ratified the treaty in October 1803. The expedition of Meriwether Lewis and William Clark soon helped map and describe the new territory.