Oklahoma City (/oʊkləˌhoʊmə -/ (listen)), officially the City of Oklahoma City, and often shortened to OKC, is the capital and largest city of the U.S. state of Oklahoma. The county seat of Oklahoma County, it ranks 20th among United States cities in population, and is the 8th largest city in the Southern United States. The population grew following the 2010 census and reached 687,725 in the 2020 census. The Oklahoma City metropolitan area had a population of 1,396,445, and the Oklahoma City–Shawnee Combined Statistical Area had a population of 1,469,124, making it Oklahoma's largest municipality and metropolitan area by population.
Oklahoma City's city limits extend somewhat into Canadian, Cleveland, and Pottawatomie counties, though much of those areas outside the core Oklahoma County area are suburban tracts or protected rural zones (watershed). The city is the eighth-largest in the United States by area including consolidated city-counties; it is the second-largest, after Houston, not including consolidated cities. The city is also the second largest by area among state capital cities in the United States, after Juneau, Alaska.
Yinchuan, referred to as "Yin", is the capital of Ningxia Hui Autonomous region, a national historical and cultural city, and one of the important central cities in Northwest China. The military, political, economic, cultural, scientific research, transportation and financial center of the autonomous region is a comprehensive industrial city focusing on the development of light and textile industry and coordinated development of machinery, chemical industry and building materials industry. Located in the middle of Ningxia Plain, located on the western edge of Ordos in the east and Helan Mountain in the west, the Yellow River runs through the city. It is a famous historical and cultural city in China, a central city in the adjacent area of Ningxia, Inner Mongolia, Shaanxi and Gansu, and a node city of the Silk Road. it is a key economic zone for the in-depth implementation of the western development strategy. Yinchuan is an ancient city with a long history. Human beings thrived at the Shuidonggou site as early as 30,000 years ago. Yinchuan, the capital of the Xixia Dynasty in history, is a famous historical and cultural city of the country.