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 comparable 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 Old Pueblo. 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 Heroica Nogales and Agua Prieta.

The Phoenix metropolitan area, also known as the Valley of the Sun, the Salt River Valley, metro Phoenix, or The Valley, is the largest metropolitan statistical area in the Southwestern United States, with its largest principal city being the city of Phoenix. It includes much of central Arizona. The United States Office of Management and Budget designates the area as the Phoenix–Mesa–Chandler Metropolitan Statistical Area (MSA), defining it as Maricopa and Pinal counties. It anchors the Arizona Sun Corridor megaregion along with the second-most populous metropolitan area in the state, the Tucson metropolitan area. The gross domestic product of the Phoenix metropolitan area was $255 billion in 2018, 16th highest amongst metro areas in the United States.