Answer:
United States and Spain
Explanation:
"The Adams–Onís Treaty (Spanish: Tratado de Adams-Onís) of 1819, also known as the Transcontinental Treaty, the Florida Purchase Treaty, or the Florida Treaty, was a treaty between the United States and Spain in 1819 that ceded Florida to the U.S. and defined the boundary between the U.S."
https://en.wikipedia.org/wiki/Adams%E2%80%93On%C3%ADs_Treaty
