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Desert Diary
History/Treaty of 1819


The Adams-Onis Treaty of 1819 finally fixed the border between the United States and New Spain, even though the U.S. maintained it had bought part of the region from France. The story begins in 1800 when Napoleon gave Spain some Italian lands in exchange for Louisiana. But when the French sold Louisiana to the US in 1803, Spain protested, citing a prior agreement with France that stated Louisiana could not be disposed of without Spain's consent.

Neither Spain nor France had specified the geographical limits of Louisiana in their transactions, and thus the real argument. Spain claimed that Louisiana was a small tract adjacent to the Mississippi River. France claimed the lands along the Gulf Mexico to the Rio Grande and territories drained by the Mississippi. John Quincy Adams, then U.S. Secretary of State, finally helped to settle the differences with the agreement that fixed the border along an irregular line beginning at the Sabine River, then north to the 42nd parallel and then to the Pacific.

Present-day Mexico, the US Southwest, including Texas, were officially in New Spain. Thus, Santa Fe and San Antonio remained Spanish settlements!
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Contributor: Florence E. Schwein, University of Texas at El Paso.

Desert Diary is a joint production of the Centennial Museum and KTEP National Public Radio at the University of Texas at El Paso.