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.

Oklahoma is a landlocked state in the South Central region of the United States. It borders Texas to the south and west, Kansas to the north, Missouri to the northeast, Arkansas to the east, New Mexico to the west, and Colorado to the northwest. Partially in the western extreme of the Upland South, it is the 20th-most extensive and the 28th-most populous of the 50 United States. Its residents are known as Oklahomans and its capital and largest city is Oklahoma City. The state's name is derived from the Choctaw words okla, 'people' and humma, which translates as 'red'. Oklahoma is also known informally by its nickname, "The Sooner State", in reference to the Sooners, settlers who staked their claims in formerly American Indian-owned lands until the Indian Appropriations Act of 1889 authorized the Land Rush of 1889 opening the land to white settlement.