February 21, 2019 will be the 200th Anniversary of the signing of the Adams–Onís Treaty, which came into full effect exactly 2 years later. The United States purchased East Florida and West Florida from Spain, the payment being in the form of assuming the claims of United States Citizens against Spain and settled the boundary between the United States and the Viceroyalty of New Spain.
England had been forced to cede both Florida’s to Spain after the Revolutionary War. By around 1800, the United States was encroaching on West Florida, particularly after the Louisiana purchase in 1803. In the next several years, the United States helped themselves to three major chunks of West Florida and ramped up demands for Spain to sell the remainder. By 1818, Spain was in the process of losing its American colonies and knew it was simple a matter of time before the United States would take Florida by force. By signing the Treaty, they were at least able to gain some border concessions out west as well as relieve themselves of millions of dollars in claims by American Citizens.
The maps below show the changes that went into effect starting February 21, 2021, though the handover of both Florida’s was not completed until July 10, 1821.
BTW, that is the correct spelling on the map. Arkansas was spelled Arkansaw until sometime during the 1820’s.
The Treaty is still considered one of the United States best efforts at diplomacy.
