Los Angeles County, officially the County of Los Angeles, in the Los Angeles metropolitan area of the U.S. state of California, is the most populous county in the United States, with more than 10 million inhabitants as of 2018. As such, it is the largest non–state level government entity in the United States. Its population is larger than that of 41 individual U.S. states. It is the third-largest metropolitan economy in the world, with a Nominal GDP of over $700 billion—larger than the GDPs of countries such as Belgium, Norway, and Taiwan. It has 88 incorporated cities and many unincorporated areas and, at 4,083 square miles, it is larger than the combined areas of Delaware and Rhode Island. The county is home to more than one-quarter of California residents and is one of the most ethnically-diverse counties in the U.S. Its county seat, Los Angeles, is also California’s most populous city and the second most populous city in the U.S., with about 4 million residents.

Source: https://en.wikipedia.org/wiki/Los_Angeles_County,_California