What 1803 acquisition nearly doubled the land area of the United States?

The Louisiana Purchase was the 1803 acquisition that nearly doubled the land area of the United States.

The United States purchased the Louisiana Territory from France through a treaty signed on April 30, 1803. The agreement transferred about 828,000 square miles of land for $15 million, or roughly three cents per acre. The territory stretched from the Mississippi River to the Rocky Mountains and from the Gulf of Mexico toward the Canadian border.

President Thomas Jefferson supported the purchase because control of New Orleans and the Mississippi River was vital to western farmers and merchants. The deal also removed France from a powerful position in the interior of North America, although its size raised constitutional questions for Jefferson.

The purchase did not instantly settle ownership or erase the presence of Indigenous nations. U.S. officials later organized exploration, administration, and settlement, while Indigenous peoples continued to resist dispossession. The territory eventually contributed to all or parts of fifteen present-day states.