Peoria Arizona spans both Maricopa and Yavapai counties due to the annexation of many miles of land .The population has grown to 154,065 according to 2010 Census Bureau. It is now the ninth largest in population in Arizona. Ironically it has now surpasses its name sake Peoria, IllinoisOne of the great tourist attractions in Peoria Arizona is that it is known as the Gateway to Lake Pleasant, which is one of the greatest water recreation area in all of Arizona. The Seattle Mariners and the San Diego Padres conduct spring training at the Peoria Sports Complex each February and March. Everything you need to know is at PeoriaSpringTraining.com.The lake, maintained hiking trails along with the sports complex make this area a resort type town and a favorite for many vacationers and snow birds.