Drive east on the 60 until the strip malls of the inner San Gabriel Valley give way to round green hills, and you arrive somewhere quieter and higher up. This is Diamond Bar, a hillside city on the seam between Los Angeles County and Orange County where, today, nearly six in ten residents are Asian and the single largest thread among them is Chinese. The story of the Chinese in Diamond Bar is the story of how a 1960s cattle-ranch suburb became one of the most prosperous Chinese American towns in the country.
The Place
Diamond Bar sits in the far eastern corner of the San Gabriel Valley, roughly 27 miles east of downtown Los Angeles, where the 57 and 60 freeways cross. It is a city of curving boulevards and homes set into the Puente Hills, with the South Coast Air Quality Management District headquarters as its best-known civic neighbour.
The ZIP codes are 91765 and 91789, the area code 909, the county Los Angeles. At the 2020 census the population was 55,072, of whom 59.24 percent, some 32,626 people, were Asian. Among them, Chinese ancestry is the most common.
It is a town that feels suburban in the most literal sense: planned, leafy, and built around the car. There is no historic main street, no dense downtown grid, just boulevards threading between hills dotted with single-family homes. What sets it apart is who fills the cul-de-sacs.
How It Became Chinese
The ranch that became a suburb
The land long predates the freeways. On 30 March 1840, Governor Juan Alvarado deeded 4,340 acres of Brea Canyon and the eastern Walnut Valley to Jose de la Luz Linares, who founded Rancho Los Nogales, the Ranch of the Walnut Trees. Over the following decades the holding passed to Ricardo Vejar, who assembled more than 10,000 acres and became one of Los Angeles County’s wealthiest landowners.
In 1918 Frederick E. Lewis bought up most of the old rancho and registered a cattle brand, a diamond above a bar, with the California Department of Agriculture. The brand gave the place its name. Lewis sold the Diamond Bar Ranch to the Bartholome family in 1943, who ran cattle on it for another thirteen years.
In the 1950s the Transamerica Corporation acquired the entire ranch to build one of the nation’s first master-planned communities. The first model homes went up at the north end of town at the end of the decade, and a building boom followed. For its first thirty years Diamond Bar was an unincorporated, largely white commuter suburb. It became a city only on 18 April 1989.
The Chinese Beverly Hills moves east
To understand why the Chinese came to Diamond Bar, you have to look west, to Monterey Park. In the 1970s a Taiwanese realtor named Frederic Hsieh began marketing the hills of Monterey Park to immigrants back in Taiwan, branding it the “Chinese Beverly Hills.” Rising tension across the Taiwan Strait and a loosened US immigration regime had created a generation of affluent, educated Taiwanese families looking for somewhere to land.
They came first to Monterey Park, then spread west to east along Valley Boulevard, through Alhambra, San Gabriel, and Arcadia. As the inner valley filled and prices climbed, the newer arrivals and the upwardly mobile pushed further out, into the four eastern towns of Hacienda Heights, Rowland Heights, Walnut, and Diamond Bar.
The ethnoburb on the hill
What sociologist Wei Li named the “ethnoburb,” a suburban ethnic cluster rather than a downtown enclave, found its eastern frontier here. By the late 1980s the Chinese community of the east San Gabriel Valley had taken shape across Diamond Bar, Walnut, Rowland Heights, and Hacienda Heights. By the 1990s a Chinese ethnoburb sprawled across more than twenty valley cities.
Diamond Bar’s appeal was specific. It offered newer, larger homes than the inner valley, hillside lots with views, and, crucially, the schools of the Walnut Valley Unified School District. For Taiwanese and, later, Hong Kong and mainland families who prized education above almost everything, that combination was decisive.
Word travelled the way it always does in immigrant communities: through relatives, through realtors, through the quiet arithmetic of school test scores. A family that arrived and prospered told a cousin, who told a colleague back in Taipei. The Chinese-language newspapers and radio stations of the San Gabriel Valley carried listings for Diamond Bar homes, and the real estate offices along Diamond Bar Boulevard learned to work in Mandarin and Cantonese.
The change was fast. In 2000, census mappers found Chinese and Mexican to be the most common ancestries in Diamond Bar, with Taiwan and Korea among the most common foreign birthplaces. Between 2000 and 2010 the number of majority-Asian cities in the San Gabriel Valley doubled from six to twelve. Diamond Bar was one of them, and it has stayed that way.
The Landmarks
Diamond Bar Center, 1600 Grand Avenue. The city’s 22,500-square-foot event hall sits in Summitridge Park, its Grand View Ballroom seating 438 for dinner with the San Gabriel Valley spread out below. On weekends it fills with Chinese wedding banquets, full-moon celebrations, and graduation parties, the civic equivalent of a banquet restaurant’s round tables.
H Mart, 2825 S Diamond Bar Boulevard. The anchor of H-Mart Plaza, this large-format Korean-founded supermarket draws Chinese shoppers from across the eastern valley for its live seafood tanks, prepared-food counters, and bakery. The plaza around it is a working-day hub of Asian groceries and casual restaurants.
99 Ranch Market, Diamond Bar. The flagship Chinese American grocery chain, owned by Buena Park’s Tawa Supermarket, keeps a Diamond Bar store stocked with imported produce, dried goods, and a seafood counter where Cantonese and Mandarin are the languages of negotiation. For many families it is the weekly anchor of the kitchen.
Diamond Bar High School, 21400 Pathfinder Road. The crown jewel of Walnut Valley Unified, ranked among the top high schools in California, with a student body that is roughly 72 percent Asian. Its college-admissions results are a major reason Chinese families choose the town, and a frequent topic at the dinner table.
Diamond Bar Golf Course, 22751 Golden Springs Drive. The Los Angeles County 18-hole course on the city’s edge doubles as a banquet venue and a fixture of local life. Its clubhouse and Golden Springs corridor sit at the heart of the older, lower town, where the first Asian families settled.
Hsi Lai Temple, 3456 S Glenmark Drive, Hacienda Heights. Just over the hill, the largest Chinese Buddhist monastery in the Western Hemisphere opened in 1988 as the North American headquarters of Taiwan’s Fo Guang Shan order. For Diamond Bar’s Taiwanese families it is the spiritual centre, a short drive away through the Puente Hills.
Where They Came From
The first and defining wave was Taiwanese. The families who built the eastern valley’s Chinese community in the 1970s and 1980s came largely from Taiwan, often via Monterey Park, carrying capital, professional degrees, and an unbending faith in schooling.
They were followed, as the decades turned, by immigrants from Hong Kong and then from mainland China, especially after the loosening of mainland emigration in the 1990s and 2000s. The newer mainland arrivals tilted the community’s accent from Taiwanese-inflected Mandarin and Cantonese toward standard Mandarin, and broadened its regional cooking.
Many had first touched down elsewhere in the valley, in Monterey Park or Hacienda Heights, before trading up to Diamond Bar once a business succeeded or a down payment came together. The move east was often a move up, a marker that a family had arrived.
What united them was less a single home province than a shared trajectory: educated, often urban, choosing a hillside American suburb precisely because it promised good schools, safe streets, and room for a family to rise.
Diamond Bar Today
Diamond Bar today is a settled, prosperous Chinese American town rather than a frontier. The supermarkets, the banquet halls, the cram schools, and the boba shops are simply part of the landscape, no longer novel. A child who started kindergarten here in the 1990s now sends children of their own to the same district.
It is not a city of dense Chinatown streetscapes. The Chinese presence reads in the supermarket plazas off Diamond Bar Boulevard and Golden Springs Drive, in the trilingual signage, in the weekend traffic to Rowland Heights for dim sum, and most of all in the schools. Diamond Bar shares this hillside Chinese suburbia with neighbouring Walnut, and looks west to the older, denser Chinese towns of Monterey Park, Arcadia, and the mansions of San Marino.
The population has dipped slightly since 2020, part of a wider valley pattern as some second-generation families move to Orange County or out of state. But Diamond Bar remains, by any measure, one of the anchors of the eastern San Gabriel Valley’s Chinese world: affluent, education-obsessed, and very much at home on its hill.
Frequently Asked Questions
What percentage of Diamond Bar is Chinese?
At the 2020 census Diamond Bar was 59.24 percent Asian, about 32,626 of 55,072 residents, and Chinese is the single most common ancestry within that group. The Chinese in Diamond Bar form the largest community in a town that is majority Asian.
Why did so many Chinese families move to Diamond Bar?
The draw was the combination of newer hillside homes, lower density than the inner San Gabriel Valley, and the highly ranked Walnut Valley Unified schools. As Monterey Park and the inner valley filled in the 1980s, affluent Taiwanese and later mainland families pushed east to Diamond Bar.
Are Diamond Bar’s Chinese residents mostly Taiwanese or mainland Chinese?
The founding wave from the 1970s and 1980s was overwhelmingly Taiwanese, often arriving via Monterey Park. Later decades brought Hong Kong and mainland Chinese immigrants, so the community today blends all three, with Taiwanese roots running deepest.
What is the history of Diamond Bar before the Chinese community?
The land was the Diamond Bar Ranch, named for a cattle brand registered in 1918. Transamerica Corporation bought the ranch in the 1950s to build a master-planned suburb, and the city incorporated in 1989, just as the Chinese in Diamond Bar were beginning to arrive in number.
Where do Chinese families in Diamond Bar shop and eat?
Asian supermarkets such as H Mart on Diamond Bar Boulevard and 99 Ranch Market anchor the grocery scene, while families often drive to neighbouring Rowland Heights for dim sum and regional Chinese restaurants. Supermarket plazas off Diamond Bar Boulevard and Golden Springs Drive serve as everyday hubs.
How good are Diamond Bar’s schools?
Diamond Bar High School is ranked among the top high schools in California and is roughly 72 percent Asian. The strength of the Walnut Valley Unified School District is the central reason many Chinese families chose the town.
If your family’s story passed through Diamond Bar, or any of the places Chinese families have made home in America, Atlas of Home can trace that journey. From a flight out of Taipei to a hillside house above the San Gabriel Valley, to wherever you are now.