Cerritos is a city in Los Angeles County, California, United States, and is one of several cities that constitute the Gateway Cities of southeast Los Angeles County. It was incorporated on April 24, 1956. As of 2019, the population was 49,859. It is part of the Los Angeles–Long Beach–Anaheim, California Metropolitan Statistical Area designated by the Office of Management and Budget.

The Gateway Cities Region, or Southeast Los Angeles County, is an urbanized region located in southeastern Los Angeles County, California, between the City of Los Angeles proper, Orange County, and the Pacific Ocean. The cluster of cities has been termed "Gateway Cities" in that they serve as a "gateway" between the LA and Orange counties, with the city of Cerritos equidistant from Downtown L.A., Long Beach, and Santa Ana in Orange County. As such, the area is central to the Los Angeles-Long Beach-Anaheim, CA Metropolitan Statistical Area (MSA), and has a population of approximately 2,000,000 residents.