Green Valley is a census-designated place in Pima County, Arizona, United States. The population was 17,283 at the 2000 census. Green Valley is twenty miles south of Tucson and 40 miles north of Nogales, Sonora, Mexico. Surrounded by copper mines, and near the hiking and birding areas of the Santa Rita Mountains, Green Valley is now an unincorporated retirement community composed of 59 Homeowner Associations.
The largest of the mines are the Sierrita Mine owned by Phelps Dodge and the Mission Mine of ASARCO. Compared to other mines in Arizona the two mines are large Sierrita is low-grade.