Spain surrendered its claims to New Orleans and the Mississippi River valley to France in 1800.
The correct answer is Spain. To find the answer, you can either do a quick search online or consult a history book. In this case, you can search for the specific event in 1800 when a country surrendered its claims to New Orleans and the Mississippi River valley to France. By doing so, you will find that it was Spain that surrendered its territory to France during that time.
