The Louisiana Purchase occurred in 1803, when the United States acquired approximately 828,000 square miles of territory from France. This significant land deal, negotiated by President Thomas Jefferson, aimed to secure land for agricultural expansion and control of the Mississippi River, which was crucial for trade. The purchase doubled the size of the United States, providing vast resources and fostering westward expansion. This acquisition also sparked debates over slavery and states’ rights, as new territories were incorporated into the Union. Ultimately, the Louisiana Purchase played a crucial role in shaping the U.S. into a continental power and laid the groundwork for future expansion.