Long Beach is a coastal city in southeastern Los Angeles County, California, United States. It is the 44th-most populous city in the Unit…Long Beach is a coastal city in southeastern Los Angeles County, California, United States. It is the 44th-most populous city in the United States, with a population of 451,307 as of 2022. A charter city, Long Beach is the 7th-most populous city in California, the 2nd-most populous city in Los Angeles County, and the largest city in California that is not a county seat.