Phoenix (/ˈfiːnɪks/ FEE-niks; Navajo: Hoozdo; Spanish: Fénix or Fínix,[citation needed] Walapai: Banyà:nyuwá) is the capital and most populous city of the U.S. state
of Arizona, with 1,608,139 residents as of 2020. It is the fifth-most populous city in the United States, and the only U.S. 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 4.85 million people as of 2020. Phoenix, the seat of Maricopa County, has the largest area of all cities in Arizona, with an area of 517.9 square miles (1,341 km2), and is also the 11th largest city by area in the United States. It is the largest metropolitan area, both by population and size, of the Arizona Sun Corridor megaregion.
Haixi Mongolian and Tibetan Autonomous Prefecture, Qinghai Autonomous Prefecture, referred to as Haixi Prefecture, is located in the north of the Qinghai-Tibet Plateau and the west of Qinghai Province, with high terrain in the northwest and low in the southeast, which is a typical alpine and dry continental climate zone; the state has a total area of 300700 square kilometers and has jurisdiction over 3 county-level cities, 3 counties and 1 administrative region; in 2017, the resident population is 515200. Haixi Mongolian and Tibetan Autonomous Prefecture is the Qudi of the Qinghai-Tibet Plateau, with Tibet in the south, Gansu in the north and Xinjiang in the west. It is at the center of the confluence of the four provinces and regions of Qinghai, Gansu and New Tibet, and was once the auxiliary road of the ancient "Silk Road" leading to the Western region. Lanxila optical cable, Qingxin optical cable, Qinghai-Tibet 750 kV AC / DC interconnection line run through the whole territory, Golmud-Lhasa product oil pipeline and Xianning-Lanlan gas pipeline are distributed, Qinghai-Tibet railway and national highway.