The Adams–Onís Treaty (Spanish: Tratado de Adams-Onís) of 1819, also known as the Transcontinental Treaty, the Florida Purchase Treaty, or the Florida Treaty, was a treaty between the United States and Spain in 1819 that ceded Florida to the U.S. and defined the boundary between the U.S. and New Spain. It settled a standing border dispute between the two countries and was considered a triumph of American diplomacy. It came in the midst of increasing tensions related to Spain's territorial boundaries in North America against the United States and Great Britain in the aftermath of the American Revolution; it also came during the Latin American wars of independence.
Map showing results of the Adams–Onís Treaty.
|Signed||February 22, 1819|
|Effective||February 22, 1821|
|Expiry||April 14, 1903|
|Citations||8 Stat. 252; TS 327; 11 Bevans 528; 3 Miller 3|
|Terminated by the treaty of friendship and general relations of July 3, 1902 (33 Stat. 2105; TS 422; 11 Bevans 628).|
Florida had become a burden to Spain, which could not afford to send settlers or garrisons, so the Spanish government decided to cede the territory to the United States in exchange for settling the boundary dispute along the Sabine River in Spanish Texas. The treaty 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 the U.S. claims on parts of Spanish Texas west of the Sabine River and other Spanish areas, under the terms of the Louisiana Purchase.
The treaty remained in full effect for only 183 days: from February 22, 1821, to August 24, 1821, when Spanish military officials signed the Treaty of Córdoba acknowledging the independence of Mexico; Spain repudiated that treaty, but Mexico effectively took control of Spain's former colony. The Treaty of Limits between Mexico and the United States, signed in 1828 and effective in 1832, recognized the border defined by the Adams–Onís Treaty as the boundary between the two nations.
The Adams–Onís Treaty was negotiated by John Quincy Adams, the Secretary of State under U.S. President James Monroe, and the Spanish "minister plenipotentiary" (diplomatic envoy) Luis de Onís y González-Vara, during the reign of King Ferdinand VII.
Spain had long rejected repeated American efforts to purchase Florida. But by 1818, Spain was facing a troubling colonial situation in which the cession of Florida made sense. Spain had been exhausted by the Peninsular War (1807–1814) against Napoleon in Europe and needed to rebuild its credibility and presence in its colonies. Revolutionaries in Central America and South America had been waging wars of independence since 1810. Spain was unwilling to invest further in Florida, encroached on by American settlers, and it worried about the border between New Spain (a large area including today's Mexico, Central America, and much of the current US Western States) and the United States. With minor military presence in Florida, Spain was not able to restrain the Seminole warriors who routinely crossed the border and raided American villages and farms, as well as protected southern slave refugees from slave owners and traders of the southern United States.
While fighting escaped African-American slaves, outlaws, and Native Americans in U.S.-controlled Georgia during the First Seminole War, American General Andrew Jackson had pursued them into Spanish Florida. He built Fort Scott, at the southern border of Georgia (i.e., the U.S.), and used it to destroy the Negro Fort in northwest Florida, whose existence was perceived as an intolerable disruptive risk by Georgia plantation owners.
To stop the Seminole based in East Florida from raiding Georgia settlements and offering havens for runaway slaves, the U.S. Army led increasingly frequent incursions into Spanish territory. This included the 1817–1818 campaign by Andrew Jackson that became known as the First Seminole War, after which the U.S. effectively seized control of Northeastern Florida; albeit for purposes of lawful government and administration (in the state of Georgia); but not for the outright annexation of territory for Georgia; for additional US Territory; or, for the creation of another U.S. state.
Adams said the U.S. had to take control because Florida (along the border of Georgia and Alabama Territory) had become "a derelict open to the occupancy of every enemy, civilized or savage, of the United States, and serving no other earthly purpose than as a post of annoyance to them." Spain asked for British intervention, but London declined to assist Spain in the negotiations. Some of President Monroe's cabinet demanded Jackson's immediate dismissal for invading Florida, but Adams realized that his success had given the U.S. a favorable diplomatic position. Adams was able to negotiate very favorable terms.
In 1521, the Spanish Empire created the Virreinato de Nueva España (Viceroyalty of New Spain) to govern its conquests in the Caribbean, North America, and later the Pacific Ocean. In 1682, La Salle claimed La Louisiane for France. For the Spanish Empire, this was an intrusion into the northeastern frontier of Nueva España. In 1691, Spain created the Province of Tejas in Nueva España in an attempt to inhibit French settlement west of the Mississippi River. Fearing the loss of his American territories in the Seven Years' War, King Louis XV of France ceded La Louisiane to King Charles III of Spain with the secret Treaty of Fontainebleau in 1762. The Treaty of Paris of 1763 split La Louisiane with the portion east of the Mississippi River becoming a part of British North America and the portion west of the river becoming the District of Luisiana of Nueva España. This eliminated the French threat to Nueva España, and the Spanish provinces of Luisiana, Tejas, and Santa Fe de Nuevo México coexisted with only loosely defined borders. In 1800, French First Consul Napoleon Bonaparte forced King Charles IV of Spain to cede Luisiana to France with the secret Third Treaty of San Ildefonso. Spain continued to administer Luisiana until 1802, when Spain publicly transferred the district to France. The following year, Napoleon sold La Louisiane to the United States to raise money for his military campaigns.
The United States and the Spanish Empire disagreed over the territorial boundaries of the Louisiana Purchase of 1803. The United States maintained the claim of France that Louisiana included the Mississippi River and "all lands whose waters flow to it." To the west of New Orleans, the United States assumed the French claim to all land east and north of the Sabine River.