Which president negotiated the Louisiana Purchase for the United States in 1803?

Thomas Jefferson negotiated the Louisiana Purchase for the United States in 1803. The agreement acquired the Louisiana territory from France during Jefferson’s presidency.

Jefferson initially authorized James Monroe and Robert R. Livingston to seek New Orleans and improve American access to the Mississippi River. French representatives instead offered the entire territory, and the American negotiators agreed to purchase it. The United States paid $15 million, including the assumption of certain claims by American citizens against France.

The purchase nearly doubled the nominal size of the United States and added land that later became parts of fifteen present-day states and two Canadian provinces. Jefferson had constitutional doubts about the federal government’s authority to acquire territory, but he ultimately supported ratification and implementation of the agreement.