It was another sun-kissed afternoon in Huntington Beach this week, the seafront a playground. Surfers skimmed the waves. Volleyballers leaped and shrieked. Sunbathers splayed on the sand. Families paraded the boardwalk.

Almost everyone had brown skin, though really they were white, just with tans. Those with permanent brown skin, Latinos, were mostly miles inland, on the other side of the 405 freeway.

“It’s called life. In this world, no one gets along, so you hang out with your own kind,” said Ruben Montanez, 54, in shorts and shades, perched on a bench.

His heritage was Puerto Rican, but Montanez did not identify with, nor yearn to see, the absent Latinos. Huntington Beach was fine just as it was. “When a neighborhood goes downhill, people leave.”

There is little chance the social services worker will feel forced to flee his home, at least not on account of Latinos.

Orange County, a cluster of cities and freeways tucked between Los Angeles and San Diego, is known for being white and politically conservative. California’s Republican bastion, it helped launch Richard Nixon and Ronald Reagan, who called it the place “where all the good Republicans go to die”.

It led the state’s crackdown on illegal immigration in the 1990s. A sub-group of neo-Nazi surfers acquired notoriety for daubing swastikas on boards. The Real Housewives of Orange County, a reality TV show, has bolstered the impression of a white enclave.

In fact, over the past two decades, the county has become diverse to the point that whites are no longer a majority. They make up 44% of the population of 3 million, with Latinos comprising 34% and Asians 18%.

But melting pot it is not. Most whites live in tracts that are at least 60% white, many of them coastal cities such as Newport Beach, Huntington Beach, Laguna Beach and San Clemente. The inland city of Santa Ana, in contrast, once predominantly white, is now 78% Latino.

Economics explains much of this. Whites are wealthier and can afford pricey coastal real estate. Most Latinos cannot. Many observers have long suspected racism, too, but the evidence has been anecdotal.

Now there is an academic study bolstering the case that racism does indeed fuel the segregation. Celia Lacayo, a postdoctoral scholar at UCLA’s Institute of American Cultures, has published a report titled Latinos Need to Stay in Their Place: Differential Segregation in a Multi-Ethnic Suburb.

It is based on in-depth interviews with 40 white residents in 2010, conducted by two white researchers Lacaya contracted to encourage candour. The random sample was aged 25 to 61 and mostly middle to upper class professionals involved in law, real estate, sales and marketing.

A small sample, but with striking findings. The respondents “overwhelmingly characterized Latinos and African Americans as culturally deficient, problematic and inferior”, according to Lacayo. They used words like “trash”, “third world” and “gangy”.

Laurie Anaya, a Latina with a white husband, laughed off the fact that neighbors used to assumed she was the maid. ‘The maids thought it, too.’ Her friend Marilyn Johnson, 48, said her children were half-Mexican and had never encountered racism in Huntington Beach. Photograph: Rory Carroll/The Guardian

Asians, in contrast, were deemed assimilated to white American norms and values. “The Asians come in and they’re freaking motivated. Hispanics aren’t,” said one respondent. “Asians seem to be more proper, cleaner and conservative,” said another.

Many residents, Lacayo found, have split the county between the relatively diverse north and the whiter south, with freeways “functioning as a Mason-Dixon line”. People made intentional decisions to keep it so, she wrote. “Most respondents admit that they made a conscious choice to live in overwhelmingly white neighborhoods, and far away specifically from Latinos.”

Examples included a 42-year-old repo company owner named Mark. “Hispanics, they just don’t fit in,” he told the researchers. “The Mexicans go to the beach, and I don’t know why they always swim in their clothes ... They have a wet dirty blanket and they’ll drag it, and they’ll stop on the boardwalk. They’ll just stop there. And it’s like: ‘Get out of the way. How stupid are you?’”

In an interview this week, Lacayo said whites used parking fees, homeowner association rules and gated communities to deter unwanted visitors and settlers, even middle-class Latinos. They resisted the transport of Latino children to white-majority schools and expressed willingness to withdraw their children from integrated schools.

Those interviewed by the Guardian on the boardwalk – a very unscientific sample of teenagers, fortysomethings and pensioners – bristled at any suggestion of prejudice. “It’s not segregation. We all get on. It’s just that people are more comfortable with their own culture,” said one 15-year-old girl.

Ask a Mexican and you get a very different perspective. Not just any Mexican - Gustavo Arellano, editor of the alternative magazine OC Weekly and author of the syndicated column ¡Ask a Mexican!, which answers reader queries about Latino stereotypes.

Donald Trump’s head – the remnant of a piñata smashed at a protest rally when the presidential candidate visited Orange County – adorns the entrance to Arellano’s office. Which is apt, because the paper’s first Latino editor swings an ax at the county’s record.

Arellano, 37, has delighted and enraged readers by denouncing the absence of blacks and referring to Santa Ana as SanTana, the way Latinos pronounce the city’s name. Trolls routinely assail Arellano (and still ask about Latinos wearing clothes in the sea), but public discourse has evolved, he said. “We’re beyond the era of outright racism. No politician is stupid enough to be that blatant anymore. They code it as about illegal immigration.”

He thinks the “old Orange County” is dying, giving way to millennials who were reared by Mexican maids and eat Mexican food. “Which makes them half Mexican.” Progressive, artsy types who used to flee the Stepford Wives-type vibe were now staying to create a new Orange County, he said. “You have to fight the belly right in its beast.”

Gustavo Arellano, editor of OC Weekly, holds the remnants of a Donald Trump piñata. Photograph: Rory Carroll/The Guardian

The Orange County Register recently crunched census data showing the region had become slightly more diverse since 2000, largely due to Latinos and Asians moving into white areas. The median of the Diversity Index, a statistical tool, nudged from 48 to 54, meaning that in a typical neighborhood there is a better than even chance that two random residents will belong to different ethnic groups. But unless whites move to Latino areas such as Santa Ana, which demographers say is unlikely, the metropolis will remain segregated.



Still, even Huntington Beach yields little surprises. Richard, a 35-year-old longshoreman who declined to give his last name, was in a Mexican restaurant tucking into a taco. White male, blue-collar job, from a family of Trump supporters. But he himself loathed the GOP candidate.

So did somebody else in his neighbourhood, he smiled, showing a photo on his phone: a car with a Trump sticker vandalised with spray paint. “Fuck Trump. Trump Chump.”