The Spanish Cession includes land that makes up all of present-day Florida, and parts of present-day Louisiana, Mississippi, Colorado, and Alabama. It was given to the United States in the Adams-Onís Treaty

Adams-Onís Treaty

The Adams–Onís Treaty of 1819, also known as the Transcontinental Treaty or the Purchase of Florida, was a treaty between the United States and Spain in 1819 that gave Florida to the U.S. and set out a boundary between the U.S. and New Spain . It settled a standing border dispute between the two...

 of 1819, after Andrew Jackson

Andrew Jackson

Andrew Jackson was the seventh President of the United States . Based in frontier Tennessee, Jackson was a politician and army general who defeated the Creek Indians at the Battle of Horseshoe Bend , and the British at the Battle of New Orleans...

 invaded Spanish forts in Spanish Florida

Spanish Florida

Spanish Florida refers to the Spanish territory of Florida, which formed part of the Captaincy General of Cuba, the Viceroyalty of New Spain, and the Spanish Empire. Originally extending over what is now the southeastern United States, but with no defined boundaries, la Florida was a component of...

 without approval from the current president, James Monroe

James Monroe

James Monroe was the fifth President of the United States . Monroe was the last president who was a Founding Father of the United States, and the last president from the Virginia dynasty and the Republican Generation...

. US Secretary of State John Quincy Adams

John Quincy Adams

John Quincy Adams was the sixth President of the United States . He served as an American diplomat, Senator, and Congressional representative. He was a member of the Federalist, Democratic-Republican, National Republican, and later Anti-Masonic and Whig parties. Adams was the son of former...

 argued that Jackson's actions were justified because the Spanish could not maintain control of their Florida colony, thus allowing Seminoles and runaway slaves to harass the US border. Spain therefore ceded the territory to the United States, on the condition that the United States pay up to five million dollars to cover the claims made by American citizens against Spain. The Cession included West

West Florida

West Florida was a region on the north shore of the Gulf of Mexico, which underwent several boundary and sovereignty changes during its history. West Florida was first established in 1763 by the British government; as its name suggests it largely consisted of the western portion of the region...

 and East Florida

East Florida

East Florida was a colony of Great Britain from 1763–1783 and of Spain from 1783–1822. East Florida was established by the British colonial government in 1763; as its name implies it consisted of the eastern part of the region of Florida, with West Florida comprising the western parts. Its capital...

. A small portion of what is now Colorado was also ceded in Spanish due to discrepancies in the border resulting from the treaty.

Sources

• Treaty Text from the Avalon Project
• Text of the Adams-Onís Treaty