Prior to 1975, most of the few Cambodians in the United States were children of high-income families or had government-funded scholarships sent abroad to attend school. There was no history of immigration from Cambodia into the United States. After the fall of Phnom Penh to the communist Khmer Rouge in 1975, a few Cambodians managed to escape but it was only after the régime was overthrown in 1979 did large waves of Cambodians began immigrating to the US as refugees. Between 1975 and 1994, nearly 158,000 Cambodians were admitted. About 149,000 of them entered the country as refugees, and 6,000 entered as immigrants and 2,500 as humanitarian and public interest parolees. To encourage rapid cultural assimilation and to spread the economic impact, the US government settled the refugees in various towns and cities throughout the country. However, once established enough to be able to communicate and travel, many Cambodians began migrating to certain places that the climate was more like home, they knew friends and relatives had been sent, or there were rumored to be familiar jobs or higher government benefits. Consequently, large communities of Cambodians took root in cities such as Long Beach, Fresno and Stockton in California;Providence, Rhode Island; Cleveland, Ohio; as well as Lynn and Lowell in Massachusetts; and Seattle and Portland in the Pacific Northwest.
Since 1994, Cambodians admitted into the United States have entered the country as immigrants and not as refugees, but the number per year is small. Most of the increase in the ethnic Cambodian population in the can be attributed to American-born children of Cambodian immigrants or of people of Cambodian descent.
The 2010 census counted 276,667 persons of Cambodian descent in the United States, up from 206,052 in 2000. Of them, 231,616 (84%) are all-Cambodian and 45,051 part-Cambodian.
The states with the highest concentration of Cambodian American residents are Rhode Island (0.5%; 5,176), Massachusetts (0.4%; 25,387), Washington (0.3%; 19,101), California (0.2%; 86,244), and Minnesota (0.2%; 7,850).
In Southern California, there is a large Cambodian population in Long Beach, and smaller yet significant communities of Cambodians are present in Los Angeles and San Diego metropolitan areas. Four percent of Long Beach's population is of Cambodian descent, mainly concentrated on the city's east section, where there is a Cambodia Town neighborhood. Long Beach, California, has the highest population of people of Cambodian ancestry outside of Cambodia itself. The Pueblo Del Rio housing projects in South Los Angeles were home to around 200 Cambodian families in the 1980s, and as of 2010, remains a smaller but sizable Cambodian American community. The Los Angeles Chinatown has more than 600 Cambodian residents. Santa Ana, California, is 0.5% Cambodian American. The City Heights neighborhood in eastern San Diego has a large concentration of Cambodians.
In Northern California, Stockton, Modesto, and Oakland have significant Cambodian populations, while San Jose, Santa Rosa and Sacramento have sizable communities as well. Outside of California, the Pacific Northwest is home to another large Cambodian settlement, specifically in cities such as Tacoma, where Cambodians enumerate at thousands, or 1.6% of the population. There are also growing Cambodian American communities in Las Vegas, Nevada; Phoenix, Arizona; Salt Lake City, Utah; and Denver, Colorado, as the Asian American population continues to rapidly increase in Nevada, Arizona, Utah, and Colorado.
Lowell, Massachusetts, has the second highest population of Cambodian Americans of in the U.S., and is a center of Cambodian population on the east coast. 13% of its population is of Cambodian descent. Cambodian immigrants settled in Lowell during the mid-1980s, where they opened dozens of small businesses. Lynn, Massachusetts, which is nearby Lowell, has the third largest Cambodian American population. Within New England, Providence, Rhode Island, and Portland, Maine (647 residents; 1%), also contain sizable Cambodian American populations. Outside of New England, Philadelphia, Pennsylvania, and the Washington, D.C. metropolitan area have many residents of Cambodian descent. 480 people of Cambodian descent reside in Utica, New York.
In the South, there is a sizable community of Cambodian Americans in Jacksonville, Florida. 1,700 people of Cambodian descent live in Jacksonville. In Spartanburg County, South Carolina, there are 1,123 Cambodian Americans (0.4% of the county). There are very sizable Cambodian American communities in Charlotte, North Carolina, and the Atlanta metropolitan area. There is a Cambodian community in the New Orleans metropolitan area, especially in the town of Buras, Louisiana, which is 9% Cambodian. Many Cambodian immigrants in Plaquemines Parish, Louisiana, are employed as shrimpers and fishermen. There are some Cambodian Americans in Marietta, Georgia, Stone Mountain, Georgia and majority in Riverdale, Georgia. In Riverdale Georgia they have Cambodian Town. There is a nonprofit organization in Georgia called the Cambodian American Association of Georgia.
The Minneapolis–Saint Paul, Minnesota, metropolitan area has been a home to many Southeast Asian refugees, mainly Hmong, but also have thousands of Cambodian American residents. Rochester, Minnesota, is 1.2% Cambodian American. As of 2010, there were 1,600 Cambodian Americans living in Columbus, Ohio (0.2%), many of whom live in the Hilltop neighborhood. In Chicago, Illinois, there is a Cambodian community in the Albany Park neighborhood.
Aside from personal memoirs of coming to America, such as those by Loung Ung, a few books have been dedicated to studying the Cambodian American population, such as Khmer American: Identity and Moral Education in a Diasporic Community by Nancy J. Smith-Hefner. The book is an anthropological study of Khmer refugee families, largely from the perspective of the parental generation, residing in metropolitan Boston and eastern Massachusetts. This book was one of the early books among the few circulating that talks about this diasporic community. It exhibits some understanding of both traditional Khmer culture and contemporary American society, but it is not a historical study of Khmer Americans. A more recent book is Buddha Is Hiding, written by Aiwha Ong, an ethnographic study that tells the story of Cambodian Americans and their experiences of American citizenship. The study primarily investigated Khmer refugees in Oakland and the San Francisco Bay Area. The experiences portrayed in the book exemplify what most Cambodian refugees face when dealing with American institutions such as health care systems, welfare, law, police force, church, and school. The book reveals, through extensive ethnographic dialogues, how Cambodian refugees interpret and negotiate American culture, often at the expense of their own Theravada Buddhist cultural upbringing.
Survivors: Cambodian Refugees in the United States, written by Sucheng Chan, is a multidisciplinary study of Cambodian Americans drawing on interviews with community leaders, government officials, and staff members in community agencies as well as average Cambodian Americans to capture perspectives from a variety of socioeconomic backgrounds.
Two museums in the US are devoted to the story of Cambodians in America, the Cambodian Cultural Museum and Killing Fields Memorial in Seattle and the Cambodian American Heritage Museum and Killing Fields Memorial in Chicago, both founded in 2004.The Seattle museum was founded by Dara Duong, a survivor of the Cambodian Genocide.
According to the 2000 census, Cambodian American populations had a lower level of education compared to other populations in the United States, with 53.4% of Cambodian Americans over the age of 25 not possessing a high school diploma, compared to 19.6% of all Americans.
In 2000, Cambodian American families reported a median household income of $36,152. A 2008 NYU study reported that 29.3% of the Cambodian American community lived under the poverty line. This was higher than the American average of people living below the poverty line which, in 2011, was recorded as 16% of all Americans.
In 2014, it was reported that Cambodia Town, Long Beach, California, the only officially-recognized ethnic enclave of Cambodian Americans, had a poverty rate of 32.4%. That was a little over twice the average of America society as a whole, which was 16%, according to a 2011 study by the government.
In 2014, a factfinder census, with Americans' per capita income being divided by ethnic groups, Cambodian Americans were revealed to have a per capita income of only $20,182, below the American average of $25,825.
The Personal Responsibility and Work Opportunity Reconciliation Act, which was signed into law by President Bill Clinton in 1996, resulted in many legal immigrants losing the federal aid that they had been receiving from the Social Security Administration. That especially affected Cambodian immigrants and other Southeast Asians, who were the largest per capita race or ethnic group receiving public assistance in the United States. Under the Indochina Migration and Refugee Assistance Act of 1975, many Southeast Asian refugees were placed on federal welfare rolls. That was intended as a temporary measure until they integrated, but by 1996, they had been stripped of their refugee status. However, nearly 80 percent of California's Southeast Asian population was living in poverty and/or welfare-dependent. That made the law have a large impact on Cambodian Americans and other citizens of Southeast Asian descent. That is a contributing factor to the high poverty rates of Cambodian Americans since the first major wave of Cambodian refugees emigrated to the United States in 1975.
Cambodians faced many difficulties upon settling in the United States, such as having few transferable job skills, speak no English, and having experienced trauma as refugees. The factors greatly impacted overall household income after resettlement. Many refugees arrived without formal education since the educated and professional classes were targeted during the genocide. That contributed to the difficulty in learning to speak English and in assimilating to the American educational system.
Another common phenomenon experienced by some Cambodian American refugees is a lack of familiarity with the history of their homeland. That is prevalent among refugees who were young children when they emigrated to the US and are now adults. Because of their age, they are not able to remember or understand the history of Cambodia that led to their family's migration. Cambodian history is only rarely taught in American public schools which contributes to that unfamiliarity, which is worsened by the resistance of older refugees to discuss the horrors that they witnessed in Cambodia.
It was estimated in 1990, five years after most arrived to the US, nearly 81% of Cambodians in America met the criteria for major affective disorder,which encompasses depression and generalized anxiety, accounting for the largest subgroup of Southeast Asians afflicted by mental health problems at the time.
One study conducted among Cambodian Americans residing in Long Beach, California, found that 13.0% of the adult respondents were current cigarette smokers. When the study was broken down by gender, 24.4% of smokers included in the study were male, and 5.4% were women. The prevalence of smoking was found to be higher in Cambodian American males than in other males residing in California. Additionally, smoking rates are estimated to be higher among Cambodian Americans than among other Asian American groups, with the prevalence of cigarette smoking among the aggregate Asian population in the US around 9.6%, with men and women combined.