Final answer:
The United States purchased Florida from Spain through the Adams-Onís Treaty in 1819.
Step-by-step explanation:
The United States purchased Florida from Spain. In 1819, the Adams-Onís Treaty was negotiated between the United States and Spain, which resulted in Spain ceding Florida to the United States. This treaty was signed in response to tensions between the United States and Spain and solidified the United States' control over the territory of Florida.
Learn more about the purchase of Florida