Mexican Americans are people who were born in the United States yet have Mexican ancestry. In 2019, Mexican Americans accounted for 11.3% of the total population in the United States and 61.5% of the total population of Hispanic and Latino Americans. 71% of Mexican Americans were born in the United States in 2019, despite the fact that Mexican Americans make up 53% of the entire population of foreign-born Latino Americans and 25% of the total population of those who were born outside the United States. The Mexican population in the United States accounts for 24 percent of the total population of people of Mexican ancestry worldwide, making it the second biggest Mexican community in the world after Mexico itself. The majority of Mexican Americans call the Southwest home; more than 60 percent of Mexican Americans live in the states of California and Texas. There are a lot of Mexican Americans residing in the United States, and a lot of them have integrate into American society. This has caused some Mexican Americans to feel less linked with their culture of origin, which may lead to an identity crisis.
The majority of Mexican Americans have some degree of Indigenous as well as European heritage, with the European ancestry often deriving from Spanish roots. Those who may claim indigenous heritage are descended from one or more of Mexico's more than 60 distinct indigenous peoples (approximately 200,000 people in California alone). It is estimated that approximately 10% of the current population of Mexican Americans are descended from early Mexican residents such as New Mexican Hispanos, Tejanos, and Californios, who became citizens of the United States in 1848 through the Treaty of Guadalupe Hidalgo, which ended the Mexican–American War. These early Mexican residents became citizens of the United States through the Treaty of Guadalupe Hidalgo. After the treaty was signed, Mexicans residing in the United States were had to make a decision: they could either preserve their Mexican citizenship or apply to become citizens of the United States. Only a few people made the decision to abandon their homes in the United States. The vast majority of these Hispanophone communities ultimately got Americanized and switched to English as their primary language of communication. These people, whose ancestors arrived in the American Southwest after the Mexican Revolution and are also known as Hispanos, differentiate themselves culturally from the population of Mexican Americans by virtue of the fact that their ancestors lived in independent Mexico during the early to middle decades of the 19th century.