History of Hispanic and Latino Americans in the United States
In 1821, Mexico gained independence from Spain, annexing the southwest of the present United States, including Arizona. As missions began to wither, Mexico began auctioning off more land, causing the Pimería Alta and the Apachería to shrink as territory expanded. In the meantime, American mountain men began to enter the region, looking to trap beavers for their pelts. In 1836, Texas declared independence from Mexico and claimed much of the territory in the northern lands of Mexico. When the United States annexed Texas in 1846 over the strong objections of the Mexican government, U.S. troops moved into disputed territory. The hostilities erupted in the Mexican–American War (1846–1848). The U.S. occupied Mexico City and forced the newly founded Mexican Republic to give up its northern half, including the later Arizona.
Republic of Texas
The region of the Mexican state of Coahuila y Tejas commonly referred to as Mexican Texas declared its independence from Mexico during the Texas Revolution in 1836. The Texas war of independence ended on April 21, 1836, but Mexico refused to recognize the independence of the Republic of Texas, and intermittent conflicts between the two states continued into the 1840s. The United States recognized the Republic of Texas in March 1837 but declined to annex the territory.