Oklahoma City is the capital and the largest city of the U.S. state of Oklahoma. It is also the county seat of Oklahoma County, Oklahoma. Oklahoma City was founded during the Land Run of 1889, first of five land runs in Oklahoma.

The city's name is often abbreviated as "O City" or its airport's IATA code, OKC. The local socialites have affectionately named it "Action City" and it is also known more recently as the Renaissance City due to its downtown renaissance. Residents of the outlying suburbs and rural areas often call it simply "The City".

Oklahoma City is a large, diverse, and growing metropolitan area; it is the civic, business, entertainment, and commercial center of the state. It is the largest city in the Great Plains region of the United States, and it is the largest city in population of the 5 "plains states" (Oklahoma, Kansas, Nebraska, North Dakota and South Dakota) in addition to six of its neighbouring states (Kansas, Missouri, Arkansas, Texas, Colorado, and New Mexico). It is also a major crossroads, being one of the very few cities in the country where three interstates "cross": Interstate 35, Interstate 40 and Interstate 44.

Oklahoma City is the 29th largest city in the nation, according to a 2004 report from the U.S. Census Bureau. The city's population on July 1, 2004 totaled 528,042, with 1.3 million residents in the metropolitan area. Oklahoma City and Tulsa have the two lowest costs of living among major U.S. cities.

Oklahoma City was the site of the bombing on the Alfred P. Murrah Federal Building in 1995, the largest act of terrorism on American soil prior to the September 11th attacks and the most destructive act of domestic terrorism in American history.