Azusa (Tongva: Asuksa-nga) is a city in the San Gabriel Valley region of Los Angeles County, California United States at the foot of the San Gabriel Mountains located 20 miles (32 km) east of downtown Los Angeles. Its population was 50,000 in 2020, an increase from 46,361 at the 2010 census. Azusa is located along historic Route 66, which passes through the city on Foothill Boulevard and Alosta Avenue. Azusa is bordered by the San Gabriel Mountains range to the north, Irwindale to the west, the unincorporated community of Vincent to the southwest, Glendora and the unincorporated community of Citrus to the east, and Covina to the south.