What territory did the United States purchase from France in 1803?

The correct answer is Louisiana. In 1803, the United States finalized the Louisiana Purchase, which involved acquiring approximately 828,000 square miles of territory from France. This acquisition doubled the size of the United States at the time and significantly expanded its borders westward. The purchase included land that would eventually become multiple states, including Arkansas, Missouri, Iowa, North Dakota, South Dakota, Nebraska, Kansas, and parts of Montana, Wyoming, Colorado, Minnesota, and New Mexico.

This pivotal move not only provided the U.S. with vast resources and land for agriculture but also facilitated further exploration and settlement of the western territories, leading to greater national development. It is one of the most significant land deals in American history and helped set the stage for the nation's growth into a continental power. The other options pertain to different historical events and territorial changes, which did not occur in 1803.