Downey is a city located in Southeast Los Angeles County, California, United States, 13 mi (21 km) southeast of Downtown Los Angeles. It is considered part of the Gateway Cities. The city is the birthplace of the Apollo space program. It is also the home of the oldest operating McDonald's restaurant in the world. As of the 2020 census, the city had a total population of 114,355.

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.