The Adams–Onís Treaty, also known as the Spanish Cession and 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 Mexico (New Spain). It settled a standing border dispute between the two countries and was considered a triumph of American diplomacy. The treaty established the boundary of U.S. territory and claims through the Rocky Mountains and west to the Pacific Ocean, in exchange for Washington paying residents’ claims against the Spanish government up to a total of $5 million Spanish dollars 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.