How the United States Acquired Florida: The Adams–Onís Treaty

The United States acquired Florida through the Adams–Onís Treaty of 1819 with Spain. Spain ceded East and West Florida to the US, giving it control of the entire peninsula. In return, the US assumed up to $5 million in claims by American citizens against Spain for damages between 1792 and 1802. The treaty was ratified in 1821, formalizing the transfer.