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 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 in Europe and needed to rebuild its credibility and presence in its colonies. Revolutionaries in Central America and South America were beginning to demand independence. 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.
By 1819, Spain was forced to negotiate, as it was losing hold on its American empire, with its western territories primed to revolt. 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 the Georgia (i.e., the U.S.), and used it to destroy the Negro Fort in northwest Florida, whose existence was perceived as an untolerable 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 & 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 General 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.[notes 1] Spain maintained that all land west of the Calcasieu River and south of the Arkansas River belonged to Tejas and Santa Fe de Nuevo México (see #New Spain.)
The United Kingdom claimed the region west of the Continental Divide between the undefined borders of Alta California and Russian Alaska on the basis of (1) the third voyage of James Cook in 1778, (2) the Vancouver Expedition in 1791–1795, (3) the solo journey of Alexander Mackenzie to the North Bentinck Arm[notes 2] in 1792–1793, and (4) the exploration of David Thompson in 1807–1812. The Third Nootka Convention of 1794 called for the joint and exclusive British–Spanish exploitation of the region.
The United States claimed essentially the same region on the basis of (1) the voyage of Robert Gray up the Columbia River in 1792, (2) the United States Lewis and Clark Expedition of 1804–1806, and (3) the establishment of Fort Astoria[notes 3] on the Columbia River in 1811. On 20 October 1818, the Anglo-American Convention of 1818 was signed setting the border between British North America and the United States east of the Continental Divide along the 49th parallel north and calling for joint Anglo-American occupancy west of the Great Divide. The Anglo-American Convention ignored the Nootka Convention of 1794 which gave Spain joint rights in the region. The Convention also ignored Russian settlements in the region. The United States referred to this region as the Oregon Country, while the United Kingdom referred to the region as the Columbia District.
On 16 July 1741, the crew of the Imperial Russian Navy ship Saint Peter (Апостол Пётр), captained by Vitus Bering, sighted Mount Saint Elias, [notes 4] the fourth-highest summit in North America. They became the first Europeans to land in northwestern North America. The Russian fur trade soon followed the discovery. By 1812, the Russian Empire claimed Alaska and the Pacific Coast of North America as far south as the Russian settlement of Fortress Ross,[notes 5] only 105 kilometers (65 miles) northwest of the Spain's Presidio Real de San Francisco.
Expandable map of Spanish claims north of Alta California 1789–1795
Expandable map of the Viceroyalty of New Spain in 1800
Expandable map of the Viceroyalty of New Spain in 1819
The Spanish Empire claimed all lands west of the Continental Divide throughout the Americas.[notes 6] Between 1774 and 1779, King Charles III of Spain ordered three naval expeditions north along the Pacific Coast to assert Spain's territorial claims. In July 1774, Juan José Pérez Hernández reached latitude 54°40′ north off the northwestern tip of Langara Island before being forced to turn south. On 15 August 1775, Juan Francisco de la Bodega y Quadra reached the latitude 59°0′ before returning south. On 23 July 1779, Ignacio de Arteaga y Bazán and Bodega y Quadra reached Puerto de Santiago onIsla de la Magdalenda (now Port Etches on Hinchinbrook Island)[notes 7] where they held a formal possession ceremony commemorating Saint James, the patron saint of Spain. This marked the northernmost Spanish exploration in the Pacific Ocean.
Between 1788 and 1793, Spain launched several more expeditions north of Alta California. On 24 June 1789, Esteban José Martínez Fernández y Martínez de la Sierra established the Spanish colony of Santa Cruz de Nuca[notes 8] on the northwest coast of Vancouver Island. Asserting Spain's claim of exclusive sovereignty and navigation rights, Martínez seized several ships in Nootka Sound provoking the Nootka Crisis with the British Empire. In negotiations to resolve the crisis, Spain claimed that its Nootka Territory extended north from Alta California to the 61st parallel north and from the Continental Divide west to the 147th meridian west. On 11 January 1794, the Spanish Empire and the British Empire signed the Third Nootka Convention which called for the abandonment of all permanent settlements on Nootka Sound. Santa Cruz de Nuca was formally abandoned on 28 March 1795. The Convention also called for joint and exclusive British–Spanish exploitation of the Nootka Territory. On 19 August 1796, the Spanish Empire joined the French First Republic in war against the British Empire with the signing of the Second Treaty of San Ildefonso, thus ending Spanish and British cooperation in the Americas.
East of the Continental Divide, the Spanish Empire claimed all land south of the Arkansas River that was west of the Medina River and all land south of the Red River that was west of the Calcasieu River.[notes 9] The vast disputed region between the territorial claims of the United States and Spain was occupied primarily by native peoples with very few traders of either Spain or the United States. In the south, the disputed region between the Calcasieu River and the Sabine River encompassed Los Adaes, the first capital of Spanish Texas. The region between the Calcasieu and Sabine rivers become a lawless no man's land. The United States saw great potential in these western lands, and hoped to settle their borders. Spain, seeing the end of New Spain, hoped to employ its territorial claims before it would be forced to grant Mexico its independence (later in 1821). Spain hoped to regain much of its territory after the regional demands for independence subsided.
Details of the treaty
Expandable map of the Adams–Onís Treaty
The treaty, consisting of 16 articles was signed in Adams' State Department office at Washington, on February 22, 1819, by John Quincy Adams, U.S. Secretary of State, and Luis de Onís, Spanish minister. Ratification was postponed for two years, because Spain wanted to use the treaty as an incentive to keep the United States from giving diplomatic support to the revolutionaries in South America. As soon as the treaty was signed, the U.S. Senate ratified unanimously; but because of Spain's stalling, a new ratification was necessary and this time there were objections. Henry Clay and other Western spokesmen demanded that Spain also give up Texas. This proposal was defeated by the Senate, which ratified the treaty a second time on February 19, 1821, following ratification by Spain on October 24, 1820. Ratifications were exchanged three days later and the treaty was proclaimed on February 22, 1821, two years after the signing.
The Treaty closed the first era of United States expansion by providing for the cession of East Florida under Article 2; the abandonment of the controversy over West Florida under Article 2 (a portion of which had been seized by the United States); and the definition of a boundary with the Spanish province of Mexico, that clearly made Spanish Texas a part of Mexico, under Article 3, thus ending much of the vagueness in the boundary of the Louisiana Purchase. Spain also ceded to the U.S. its claims to the Oregon Country, under Article 3.
The U.S. did not pay Spain for Florida, but instead agreed to pay the legal claims of American citizens against Spain, to a maximum of $5 million, under Article 11.[notes 10] Under Article 12, Pinckney's Treaty of 1795 between the U.S. and Spain was to remain in force. Under Article 15, Spanish goods received exclusive most-favored-nation privileges in the ports at Pensacola and St. Augustine for twelve years.
Under Article 2, the U.S. received ownership of Spanish Florida (British East Florida and West Florida 1763–1783). Under Article 3, the U.S. relinquished its own claims on parts of Texas west of the Sabine River and other Spanish areas.