largest city in los angeles county
LA County Population. The County of Los Angeles is the largest county in the United States based on population. According to the California Department of Finance, the LA County population as of January 1, 2015 was 10,136,559. LA County is home to 88 cities, including LA City. The population of those cities varies from 122 people in Vernon to nearly four million in the City of Los Angeles. The largest cities in LA County are: 1) Los Angeles - 3,957,022.