The Adams-Onís Treaty also called the Transcontinental Treaty or the Florida Treaty was a treaty between the United States and Spain in 1818 that gave Florida to the U.S. and set out a boundary between the U.S. and Mexico.
The treaty was signed at Washington, February 22, 1819, by John Quincy Adams, secretary of state, and Luis de Onís, Spanish minister. It closed the first era of United States expansion by providing for the cession of East Florida, the abandonment of the controversy over West Florida (which had been seized by the United States), and creation of a boundary with the Spanish province of Mexico that clearly made Texas a part of Mexico, thus ending the vagueness of the boundary of the Louisiana Purchase. Spain also gave up any claims to the Oregon territory.
The U.S. did not pay Spain for Florida but did agree to assumed claims of American citizens against Spain, to a maximum of $5 million. Pinckney's Treaty of 1795 between the U.S. and Spain was to remain in force. Spanish goods received certain tariff privileges in Florida ports.
The new boundary ran along the Sabine River from the Gulf of Mexico north to the 32nd parallel; thence north to the Red River, along it to the 100th meridian; north to the Arkansas River and along it to its source; thence to the 42nd parallel; and west on that line to the Pacific Ocean.
Spain had long rejected repeated American efforts to purchase Florida. Finally exhausted by European wars and colonial revolutions, and unwilling to invest in Florida, cut its losses and gained a secure boundary for Mexico. Spain had almost no presence of Florida and was unable to stop Seminole Indians who raided into the U.S. In 1818 Andrew Jackson's moved into the Floridas temporarily to stop the Indian raids. Britain declined to assist Spain in the negotiations. The ministers of King Ferdinand VII (reigned 1808–33) at first refused to ratify the treaty. The Spanish argued that James Long's 1819 filibustering expedition into Texas was a violation; Washington disavowed Long's actions. Spain's real goal was to stop American recognition of the independence of breakway colonies in Latin America. When Ferdinand lost some powers and became a constitutional monarch in 1820, his council was obliged to approve the treaty. Ratification became official in 1821.
Adams more than anyone else was responsible for the treaty. He was the architect of a sophisticated strategy which combined diplomatic and military means to bring Spain to terms. Adams also directed an intensive public relations campaign which maintained public and Congressional support for the administration's policy.
Washington set up a commission, 1821 to 1824, that handled American claims against Spain. Many notable lawyers, including Daniel Webster and William Wirt, represented claimants before the commission. During its term, the commission examined 1,859 claims arising from over 720 spoliation incidents, and distributed the $5 million in a basically fair manner.
The treaty reduced tensions with Spain (and after 1821 Mexico), and allowed budget cutters in Congress to reduce the army budget and reject the plans to modernize and expand the army proposed by Secretary of War John C. Calhoun.
The treaty was honored by both sides until it was replaced by the Treaty of Guadaloupe Hidalgo in 1848, after the U.S. defeated Mexico. Inaccurate maps from the treaty meant that the boundary between Texas and Oklahoma remained unclear for most of the 19th century.
- Bailey, Hugh C. "Alabama's Political Leaders and the Acquisition of Florida." Florida Historical Quarterly 1956 35(1): 17-29. Issn: 0015-4113 online version
- Bemis, Samuel Flagg. John Quincy Adams and the Foundations of American Foreign Policy. (1949), the standard history
- Cash, Peter Arnold. "The Adams-Onís Treaty Claims Commission: Spoliation and Diplomacy, 1795-1824." PhD dissertation U. of Memphis 1998. 368 pp. DAI 1999 59(9): 3611-A. DA9905078 Fulltext: ProQuest Dissertations & Theses
- DelRio, Angel. La Misión de Don Luis de Onís en los Estados Unidos (1809-1819) [The mission of Don Luis de Onís in the United States, 1809-19]. Barcelona: Talleres Novagrafik, 1981. 294 pp.
- Weeks, William E. John Quincy Adams and American Global Empire (2002)
- See Weeks (1986)
- Cash (1998)