How did mexican americans become such a large an important group in the united states

Becuase they brought difrent cultures in to the USA

The history of Mexican Americans, Americans of Mexican descent, largely begins after the annexation of parts of Mexico in 1845, the nearly 80,000 individuals then living in the U.S. became full U.S. citizens. Large-scale new migration augmented their numbers during the 1910s, as Mexico was torn by a high-casualty civil war. Until the 1960s, most lived within a few hundred miles of the border, although some resettled along frail lines from the Southwest to the Midwest.