The Phoenix Metropolitan Area – also the Valley of the Sun, the Salt River Valley, or Metro Phoenix (known by most locals simply as “the Valley”) – is the largest metropolitan statistical area in the Southwestern United States, centered on the city of Phoenix, that includes much of the central part of 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 largest 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, as 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 average United States rate of 13.2%, helping to make Arizona the second fastest growing state in the nation in the 1990s (the fastest was Nevada). The 2000 Census reported the population of the metropolitan area to be 3,251,876.