Los Angeles County, sometimes abbreviated as LA County, is a county in the U.S. state of California, in the southern region of the state. It is the most populous county in the United States, with 9,694,934 residents estimated in 2025. Its population is greater than that of 40 individual U.S. states. Comprising 88 incorporated cities and 101 unincorporated areas within a total area of 4,083 square miles (10,570 km²), it accommodates more than a quarter of Californians and is one of the most ethnically diverse U.S. counties. The county's seat, Los Angeles, is the second-most populous city in the United States, with 3,878,704 residents estimated in 2024. The county is globally known as the home of the U.S. motion picture industry since its inception in the early 20th century.