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 around $400 billion in 2023, 14th highest amongst metro areas in the United States.
As of the 2020 census, the two-county metropolitan area had 4,845,832 residents, making it the 11th largest metropolitan area in the nation by population. Metro Phoenix grew by 652,945 people from April 2010 to April 2020, making it one of the fastest growing metro areas in the country. This also contributed to the entire state's exceptional growth; the area is home to just over two-thirds of Arizona's population. The population of the Phoenix metropolitan area increased by 45.3% from 1990 through 2000, compared to the overall U.S. rate of 13.2%, helping make Arizona the second-fastest growing state in the nation in the 1990s behind Nevada. The 2000 census reported the population of the metropolitan area to be 3,251,876. Water insecurity and drought in conjunction with climate change have become a significant concern for the metropolitan area's future growth prospects.
