Final answer:
The United States initially sought to buy New Orleans from Napoleon in 1801, but ended up securing the entire Louisiana Territory in the historic Louisiana Purchase of 1803.
Step-by-step explanation:
In 1801, the United States hoped to secure the purchase of the city of New Orleans and access to the Mississippi River from Napoleon. What unfolded, however, was a much larger transaction now known as the Louisiana Purchase. President Thomas Jefferson had originally only intended to acquire New Orleans to ensure a vital port for American trade, but Napoleon, faced with financial pressure from the costs of a failed war in Haiti and the anticipation of conflict with Britain, offered the entire Louisiana Territory. The United States, seizing the unexpected opportunity, agreed to the transfer in 1803, essentially doubling the nation's size for $15 million.