Which 1803 acquisition greatly expanded the United States and is part of the history America250 surveys?

The Louisiana Purchase was the 1803 acquisition that greatly expanded the United States.

The United States bought the Louisiana Territory from France in a treaty signed on April 30, 1803. The agreement was completed during the presidency of Thomas Jefferson, and the transfer of sovereignty took place later that year. The purchase covered a vast region west of the Mississippi River and east of the Rocky Mountains, although its boundaries were not immediately clear.

The transaction added approximately 828,000 square miles to the United States. It roughly doubled the country’s geographic size and gave the United States control of the port of New Orleans, an important outlet for trade on the Mississippi River. The purchase price was $15 million, commonly summarized as about three cents per acre.

The Louisiana Purchase is distinct from later acquisitions. The Alaska Purchase came from Russia in 1867, the Gadsden Purchase came from Mexico in 1853, and the Adams–Onís Treaty transferred Florida from Spain. Together, these events form part of the territorial history leading toward the United States commemorated by America250.