The country that sold the Louisiana Territory in 1803 was France. Here's an explanation to support this answer:
1. In 1803, France, under the leadership of Napoleon Bonaparte, sold the Louisiana Territory to the United States.
2. This transaction is known as the Louisiana Purchase and was finalized through the Louisiana Purchase Treaty signed on April 30, 1803.
3. The Louisiana Territory was a vast area of land west of the Mississippi River, stretching from the Gulf of Mexico to the Canadian border, comprising approximately 828,000 square miles.
4. The purchase of the Louisiana Territory doubled the size of the United States and was a significant event in American history, shaping the expansion and development of the nation.
Therefore, the correct answer is France.
