New Spanish-American Boundary
New Spanish-American Boundary


The Adams-Onís Treaty. formally known as the Transcontinental Treaty of 1819, was negotiated between the United States and Spain. John Quincy Adams negotiated on the United States behalf with Don Luis de Onís, the Spanish Minister of Spain. Signed on February of 1819, the treaty gave the US the acquisition of Florida and established a new boundary line between Spanish and US territory.

Origins of the Treaty

After the Louisiana Purchase of 1803, President Thomas Jefferson stated that Florida was included in Louisiana. The United states annexed parts of western florida in 1810 and 1812. In 1817 John Quincy Adams became secratary of state and pursued additional territory. 1817 and 1818 resumed the efforts to gain florida under President James Monroe. After Adams and Monroe tried to gain florida, the US started negotiating an official boundary line. After several months of negotiation the Adams Onis Treaty was signed by the US Congress February 22, 1819. The treaty gave gave both east and west Florida to the United States, and the US agreed to assume claims by citizens of the United States against Spain. Spain didn't sign the treaty until two years later, 1821. After Spain's ratification Congress signed the treaty for a second time.

Problems with the Treaty

The US had to pay citizens claims rights that soared to over 5 million dollars as a result of gaining Spanish Florida. Also, Spain was undergoing serious internal problems. With bad relations with mexico and its own colonies on the brink of revolution, Spain was in a bad posistion for negotiations. While Mexico was originally not involved with the treaty, Mexico ratified it in 1831, agreeing to the boundaries. Several years after, in the mid 1830's, controversy aroused over the Texan border. Map fraud showed that the Sabine and Neches rivers were switched, resulting in territorial gain for mexico. The issue was not resolved until the Republic of Texas declared its freedom in 1836 and the Treaty of Quadalupe Hidalgo got signed (1848).


Text of the Treaty
Oklahoma Historical Societ
The Avalon Project, Yale University