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.
Shuangyashan City is a prefecture-level city in Heilongjiang Province. Shuangyashan City is located in the northeast of Heilongjiang Province, with high terrain in the southwest and low in the northeast, and is located in the humid climate zone of the middle temperate zone. It has jurisdiction over 4 districts and 4 counties, with a total area of 22483 square kilometers and a total population of 1.423 million in 2017. Within 300 kilometers of Shuangyashan, there are Tongjiang, Fuyuan and other first-class ports to Russia, which are located in the core area where Heilongjiang Province opens to the Russian far East, and is an important node city for the construction of the "China-Mongolia-Russia Economic Corridor." It has a first-class national port-Raohe Port, the Raohe Sino-Russian Exchange Trade Zone and the Sida Sino-Russian International Trade Center have been put into operation, and the Sino-Russian International Cultural Logistics Economic and Trade Industrial Park is being constructed. to build an import and export processing base for Russia and a national trade distribution base for Russia. Successively opened Shuangyashan to Haba.