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.
Ludian County is one of the counties under the jurisdiction of Zhaotong City, Yunnan Province, located in the northeast of Yunnan Province, the south of Zhaotong City, the north bank of Niulan River. The east-west horizontal distance of the county is 50 kilometers, the north-south vertical distance is 60 kilometers, and the total area is 1519 square kilometers, of which the mountain area accounts for 87.9 percent of the total area and the dam area accounts for 12.1 percent. As of 2013, Ludian County has jurisdiction over 10 towns, 2 townships (including 2 ethnic townships), a total of 4 neighborhood committees and 80 administrative villages. The county government is in Wenping town. The vertical climate change in Ludian County is obvious, with no extreme heat in summer and no severe cold in winter. The average annual temperature is 12.1 ℃, the annual frost-free period is 220 days, and the average annual precipitation is 900mm. There are silver, lead, copper, sulfur, coal, phosphorus and other mineral deposits, Lemachang silver mine in the territory. Ludian County is the main producing county of wax insects in China, and the main producing county of walnut and high quality flue-cured tobacco in Yunnan Province.