The territory acquired in the Louisiana Purchase was a vast region of land that roughly doubled the size of the United States. The purchase, made in 1803 from France under President Thomas Jefferson, included land west of the Mississippi River, encompassing parts of 15 current U.S. states from Louisiana up to Montana and Canada. This acquisition greatly enhanced agricultural potential, facilitated westward expansion, and provided vital resources. It also set the stage for future conflicts over slavery and territorial governance, shaping the nation’s development through the 19th century.