Spanish Cession

Spanish Cession

The Adams–Onís Treaty 1819, also known as the Transcontinental Treaty or the Purchase of Florida, or the Florida Treaty, was a treaty between the United States and Spain in 1819 that gave Florida to the U.S. and set out a boundary between the U.S. and New Spain (now Mexico). 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 vs. the United States and United Kingdom in the aftermath of the American Revolution; and also, during a period of weakening in Spanish power.

In addition to ceding Florida to the United States, the treaty settled (as between Spain and the national Government of the US) a boundary dispute along the Sabine River in Texas; it 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 the US claims on parts of Spanish Texas west of the Sabine River and other Spanish areas, under the terms of the Louisiana Purchase.

This latter territorial “settlement” was never accepted by American Southerners in general or Louisianans in particular. They later migrated from Louisiana territory and crossed into Spanish Texas (later the Mexican State of Texas)--firm in the belief that the original Louisiana Territory (which had been purchased nearly two decades earlier from France) included substantial tracts of land in what is now Colorado and New Mexico. They thought the western and northern borders of Texas should include what is now the eastern third of all New Mexico and the southeastern third of Colorado.