A generation ago, whites made up roughly two-thirds of the population in this rarefied Los Angeles suburb, where most of the homes are worth well over $1 million. But Asians now make up over half of the population in San Marino, which has long attracted some of the region’s wealthiest families and was once home to the John Birch Society’s Western headquarters.

The transformation illustrates a drastic shift in California immigration trends over the last decade, one that can easily be seen all over the area: more than twice as many immigrants to the nation’s most populous state now come from Asia than from Latin America.

And the change here is just one example of the ways immigration is remaking America, with the political, economic and cultural ramifications playing out in a variety of ways. The number of Latinos has more than doubled in many Southern states, including Alabama, Georgia and North Carolina, creating new tensions. Asian populations are booming in New Jersey, and Latino immigrants are reviving small towns in the Midwest.

Much of the current immigration debate in Congress has focused on Hispanics, and California has for decades been viewed as the focal point of that migration. But in cities in the San Gabriel Valley — as well as in Orange County and in Silicon Valley in Northern California — Asian immigrants have become a dominant cultural force in places that were once largely white or Hispanic.