SAN MARINO, Calif. — Beneath the palm trees that line Huntington Drive, named for the railroad magnate who founded this Southern California city, hang signs to honor families who have helped sponsor the centennial celebration here this year. There are names like Dryden, Crowley and Telleen, families that have lived here for generations. But there are newer names as well: Sun, Koo and Shi.

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.