With 10.6 million people, Los Angeles County is the most populous county in the United States. It has over one quarter of the population of the state of California. Its county seat, the City of Los Angeles, is the second most populous city in the country, with 4 million residents. The county includes 88 incorporated cities plus many unincorporated areas. The population is one of the most diverse in the nation. The median household income in L.A. County is $55,909. The median home value is $618,600.
It is 4,083 square miles in size, larger than Delaware and Rhode Island combined. There are 2 mountain ranges, the Santa Monica Mountains in the northwestern portion of the county, and the San Gabriel Mountains, running east-west across the county near its center. The southern part of the county is mostly a wide coastal plain, with beaches along the southwest and south. The northeastern part of the county is part of the Mojave Desert. San Clemente and Catalina Islands, the southernmost of the Channel Islands are part of L.A. County as well.
The county includes a wide variety of business development, particularly in the fields of transportation, aerospace and defense, pharmaceuticals and medical device, and the Hollywood entertainment industry. There are numerous schools and universities, a number of airports, and ocean ports in San Pedro and Long Beach.