Phoenix is the capital and most populous city in Arizona, with 1,680,992 people (as of 2019). It is also the fifth-most populous city in the United States, the largest state capital by population, and the only state capital with a population of more than one million residents. Phoenix is the anchor of the Phoenix metropolitan area, also known as the Valley of the Sun, which in turn is part of the Salt River Valley. The metropolitan area is the 11th largest by population in the United States, with approximately 4.73 million people as of 2017. Phoenix is the seat of Maricopa County and the largest city in the state at 517.9 square miles (1,341 km2), more than twice the size of Tucson and one of the largest cities in the United States. The flag of Phoenix, Arizona, iconsists of a maroon background and a white phoenix in the center of the flag, the same icon used in the Seal of Phoenix. Full HD.