Ciudad Obregon is the second largest city in the northern Mexican state of Sonora and 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.
The city, previously named Cajeme, takes its name from Mexican Revolutionary Álvaro Obregón, a native of nearby Huatabampo, Sonora. Álvaro Obregón became president of Mexico after the Revolution and initiated an "agricultural revolution" in the Yaqui Valley, introducing modern agricultural techniques and making this valley one of the most prosperous agricultural regions in the country. Renowned U.S. agronomist Dr. Norman Borlaug, the architect of the "Green Revolution" worked here after successful developments in increasing the resistance of wheat. For his efforts he was later awarded the Nobel Prize.