Approximately how much territory did the United States acquire through the Louisiana Purchase?

The United States acquired approximately 828,000 square miles through the Louisiana Purchase.

The purchase agreement with France was signed in 1803 for $15 million, or about three cents per acre. It transferred French claims to a vast region west of the Mississippi River and east of the Rocky Mountains, although the boundaries were not precisely defined at first.

President Thomas Jefferson supported the deal because control of the Mississippi River and New Orleans was vital to farmers and merchants in the growing United States. The acquisition more than doubled the country’s size and opened an enormous area to later exploration, settlement, territorial organization, and conflict.

The purchase did not immediately create new states. The acquired land was gradually surveyed and organized into territories. Its consequences also intensified disputes over Indigenous sovereignty and the expansion of slavery, issues that shaped United States history for decades.