Arcadia is a city in Los Angeles County, California, United States, located about 13 miles (21 km) northeast of downtown Los Angeles in the San Gabriel Valley and at the base of the San Gabriel Mountains. It contains a series of adjacent parks consisting of the Santa Anita Park racetrack, the Los Angeles County Arboretum and Botanic Garden, and Arcadia County Park. The city had a population of 56,681 at the 2020 census. The city is named after Arcadia, Greece.