Peoria is a city in Maricopa and Yavapai counties in the U.S. state of Arizona. Most of the city is located in Maricopa County, while a portion of it in the north is in Yavapai County. It is a major suburb of Phoenix. As of the 2020 census, the population of Peoria was 190,985, up from 154,065 in 2010. It is the sixth-largest city in Arizona in land area and the ninth-largest in population. It was named after Peoria, Illinois. The word peoria is a corruption of the Miami-Illinois word for "prairie fire". It is the spring training home of the San Diego Padres and Seattle Mariners, who share the Peoria Sports Complex.

Yavapai County is near the center of the U.S. state of Arizona. As of the 2020 census, its population was 236,209, making it the fourth-most populous county in Arizona. The county seat is Prescott.