The Louisiana Purchase occurred in 1803 when the United States bought the Louisiana territory from France for $15 million. The purchase was one of the crowning achievements of Thomas Jefferson’s presidency and doubled the size of the United States.
The new lands acquired by the purchase covered 828,000 square miles. France only controlled the territory for two years, having acquired it from Spain, but decided to sell the territory due to an impending war with Great Britain and financial troubles. France received less than three cents per acre for the land. The United States westward expansion began soon thereafter in 1804.
The United States sent Robert Livingstone and James Monroe to negotiate the purchase of New Orleans only, but France surprised them with an offer to sell the entire territory.