Phoenix is the capital and most populous city in Arizona, with 1,660,272 people as of 2018. It is also the fifth most populous city in the United States, 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. Source: Wikipedia