Azusa is a city in the San Gabriel Valley, at the foot of the San Gabriel Mountains in Los Angeles County, California, United States, located 20 miles east of downtown Los Angeles.
The population was 46,361 at the 2010 census, up from 44,712 at the 2000 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.