The
Adams-Onís Treaty of 1819
[1] settled a border dispute in
North America between the
United States and
Spain. The treaty was the result of increasing tensions between the U.S. and Spain regarding territorial rights at a time of
weakened Spanish power in the
New World. In addition to granting
Florida to the United States, the treaty settled a boundary dispute along the
Sabine River in
Texas and firmly established the boundary of U.S. territory and claims through the
Rocky Mountains and west to the
Pacific Ocean in exchange for the U.S. paying residents' claims against the Spanish government up to a total of $5,000,000 and relinquishing its own claims on parts of Texas west of the Sabine River and other Spanish areas.
The treaty was negotiated by John Quincy Adams, the Secretary of State under U.S. President James Monroe, and the Spanish foreign minister Luis de Onís.
While Spain at first refused to rewrite any border in favor of the U.S., Spain had been forced to negotiate because it was losing its hold on its colonial empire, with its western colonies primed to revolt. Specifically, while fighting escaped African-American slaves, outlaws and Native Americans in U.S.-controlled Georgia during the First Seminole War, Andrew Jackson had pursued them into Spanish Florida, but at the same time, he attacked and captured Spanish forts in Florida with absolutely no provocation, thus threatening war with Spain and causing national controversy. Some of Monroe's cabinet demanded Jackson's immediate dismissal, but Adams realized that it put the U.S. in a favorable diplomatic position. Although Spanish power in the New World had long been in decline, Jackson's attacks had exposed how weak Spain was in the New World to the U.S., Latin American revolutionaries, and the other European powers. Taking an aggressive stance, Adams was able to negotiate very favorable terms.
In its weakened state, it was fairly certain that Spain would lose the land to the United States following the Louisiana Purchase in 1803. Spain had questioned the validity of the purchase, stating that France had no right to sell Louisiana because such a sale went against the agreements in the Treaty of San Ildefonso, and furthermore, there was much discussion about the extent of the area that the United States had bought from France. The Spanish had a very restricted view of Louisiana, considering it to comprise the west bank of the Mississippi and the city of New Orleans. The United States on the other hand claimed that the land they bought extended all the way to the Rio Grande and the Rocky Mountains, thus encompassing much of Spain's northern colony of Coahuila y Tejas.
