The Arizona Sun Corridor, shortened Sun Corridor, is a megaregion, or megapolitan area, in the southern area of the U.S. state of Arizona. The Sun Corridor is equivalent to Indiana in both size and population. It is one of the fastest growing conurbations in the country and is speculated to double its population by 2040. The largest metropolitan areas are the Phoenix metropolitan area - Valley of the Sun - and the Tucson metropolitan area. The regions' populace is nestled in the valley of a desert environment. Similar to Southern California, the urban area extends into Mexico, reaching the communities of Nogales and Agua Prieta.