Area code 520 covers southeastern Arizona, including Tucson, Sierra Vista, and Nogales. Created in 1995 from a split with 602, it includes both urban and desert border communities, with strong influences from Mexican-American culture, military presence, and the University of Arizona. Tucson anchors the region with its arts scene and growing tech and aerospace sectors. Ten-digit dialing is required. Area code 520 reflects the cultural richness and geographic diversity of southern Arizona, serving as a symbol of binational exchange, education, and the expansive character of the Sonoran Desert.