Ciudad Obregon (Spanish pronunciation: [sjuˈðað oβɾeˈɣon]) is the second largest city in the northern Mexican state of Sonora and named for Sonoran revolutionary general and president of Mexico, Álvaro Obregón. It is situated 525 km (326 mi) south of the state's northern border with the U.S. state of Arizona. It is also the municipal seat of Cajeme municipality, located in the Yaqui Valley.