Which 1803 deal doubled the territory of the United States?

The Louisiana Purchase doubled the territory of the United States in 1803.

President Thomas Jefferson’s administration bought approximately 828,000 square miles from France for $15 million, or about three cents per acre. The agreement was signed on April 30, 1803, and the United States took possession later that year.

The purchase covered land west of the Mississippi River, including the port of New Orleans and territory reaching toward the Rocky Mountains. Its boundaries were not precisely surveyed, and the deal’s eventual interpretation helped fuel later disputes over western expansion and slavery.

Jefferson had originally sought only New Orleans and navigation rights on the Mississippi. Napoleon Bonaparte’s decision to abandon plans for a North American empire made the much larger offer possible. The acquisition enabled the Lewis and Clark expedition, which began in 1804 to map and study the new lands.