Peoria is a city in Maricopa and Yavapai counties in the state of Arizona. Most of the city is located in Maricopa County, while a tiny portion in the north is in Yavapai County. It is a major suburb of Phoenix. According to 2019 Census Bureau estimates, the population of the city is 175,961. Peoria is currently 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 Illini word for “prairie fire.” It is the spring training home of the San Diego Padres and Seattle Mariners, who share the Peoria Sports Complex.

Peoria sits in the Salt River Valley, and extends into the foothills of the mountains to the north. William John Murphy, who had worked on the Arizona Canal, recruited settlers to begin a community in Arizona, many of them from Peoria, Illinois. Albert J. and Elizabeth Straw were the first to establish residency in November 1886. They were followed by William T. and Sylvia Hanna, James M. and Clara Copes, and James and Ella McMillan, all from Peoria, Illinois relocate to what is now Peoria, Arizona. An old desert road connecting Phoenix to the Hassayampa River near present-day Wickenburg was the only major transportation route in the area until 1887, when a new road was laid out.