Oklahoma County is located in the central part of the U.S. state of Oklahoma. As of the 2020 census, the population was 796,292, making it the most populous county in Oklahoma. The county seat is Oklahoma City, the state capital and largest city. Oklahoma County is at the heart of the Oklahoma City metropolitan statistical area.

Oklahoma City, officially the City of Oklahoma City, and often shortened to OKC, is the capital and most populous 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 681,054 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.