Avondale is a city in Maricopa County, Arizona, United States, adjacent to Phoenix. As of the 2020 census, the population of the city was 89,334, up from 76,238 in 2010 and 35,883 in 2000. Avondale, incorporated in 1946, has experienced rapid residential and commercial growth in the years since 1980. Once primarily a sparsely populated farming community with many acres of alfalfa and cotton fields, Avondale has transformed into a major bedroom suburb for Phoenix.