While the Louisiana Purchase treaty was signed earlier, July 4, 1803, saw public announcement and celebration of the acquisition in the United States. The purchase from France nearly doubled the nation’s territory. It opened vast areas for exploration, trade, and eventual settlement. The deal also removed a major European power from the Mississippi Valley. Critics questioned the constitutional basis and long-term effects, but support quickly grew as the advantages became clear. The acquisition reshaped the geographic and political future of the United States.
