Los Angeles County, officially the County of Los Angeles, with a population of more than ten million people, is the most populous county in the United States. It has 88 incorporated cities and many unincorporated areas and at 4,083 square miles (10,570 km2) it is larger than the combined areas of the U.S. states of Delaware and Rhode Island. The county contains more than one quarter of all Californiaresidents and is one of the most ethnically diverse counties in the U.S.

Los Angeles County had a population of 9,818,605 in the 2010 United States Census. The racial makeup of Los Angeles County was 4,936,599 (50%) White, 1,346,865 (13.7%) Asian, 856,874 (9%) African American, 72,828 (0.7%) Native American, 26,094 (0.3%) Pacific Islander, 2,140,632 (21.8%) from other races, and 438,713 (4.5%) from two or more races.

Non-Hispanic whites numbered 2,728,321, or 28% of the population. Hispanic or Latino residents of any race numbered 4,687,889 (48%); 36% of Los Angeles County's population was of Mexican ancestry; 3.7% Salvadoran, and 2.2% Guatemalan heritage.

The county has a large population of Asians, being home to the largest concentration of immigrants who are Burmese, Cambodian, Chinese, Filipino, Indonesian, Korean, Sri Lankan, Taiwanese, and Thai in the world. The largest Asian groups of the 1,346,865 (13.7%) Asians in Los Angeles County are 4.0% Chinese, 3.3% Filipino, 2.2% Korean, 1.0% Japanese, 0.9% Vietnamese, 0.8% Indian, and 0.3% Cambodian.

Los Angeles County