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 San Gabriel River is a mostly-urban waterway flowing 58 miles (93 km) southward through Los Angeles and Orange Counties, California, in the United States. It is the central of three major rivers draining the Greater Los Angeles Area, the others being the Los Angeles River and Santa Ana River. The river's watershed stretches from the rugged San Gabriel Mountains to the heavily-developed San Gabriel Valley and a significant part of the Los Angeles coastal plain, emptying into the Pacific Ocean between the cities of Long Beach and Seal Beach.