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.
Oxnard Plain
Mexico gained its independence from Spain in 1821. With the secularization of the missions by the Mexican government in June 1836, their lands were granted as rewards for loyal service or in response to petitions by individuals. Most of the arable land was divided up into large ranchos by 1846. This opened up the Oxnard Plain to further settlement by Europeans. Control of the area was transferred to the United States under the Treaty of Guadalupe Hidalgo in 1848 and California became the 31st state in the Union in 1850. Many Mexican residents and residents who had immigrated from European countries became U.S. citizens.