Program Information Los Angeles County is one of the nation's largest counties with 4,084 square miles, and it has the largest population of any county in the nation. Today more than 10.4 million people call Los Angeles County home, residing in 88 cities and approximately 140 unincorporated areas. As a subdivision of the state, the County is charged with providing numerous services that affect the lives of all residents, including law enforcement, tax collection, public health protection, public social services, elections and flood control.