Oklahoma City is the capital and largest city of the U.S. state of Oklahoma. The county seat of Oklahoma County, the city ranks 27th among United States cities in population. The population grew following the 2010 Census, with the population estimated to have increased to 631,346 as of July 2015. As of 2015, the Oklahoma City metropolitan area had a population of 1,358,452, and the Oklahoma City-Shawnee Combined Statistical Area had a population of 1,459,758 (Chamber of Commerce) residents, making it Oklahoma's largest metropolitan area.
Oklahoma City's city limits extend into Canadian, Cleveland, and Pottawatomie counties, though much of those areas outside of the core Oklahoma County area are suburban or rural (watershed). The city ranks as the eighth-largest city in the United States by land area (including consolidated city-counties; it is the largest city in the United States by land area after Houston whose government is not consolidated with that of a county or borough).
Oklahoma City has the largest municipal population of any city in the Great Plains region of the central United States as well as all neighboring states to Oklahoma, excluding Texas and Colorado.
Lying in the Great Plains region, Oklahoma City has one of the world's largest livestock markets. Oil, natural gas, petroleum products and related industries are the largest sector of the local economy. The city is in the middle of an active oil field and oil derricks dot the capitol grounds. The federal government employs large numbers of workers at Tinker Air Force Base and the United States Department of Transportation's Mike Monroney Aeronautical Center (these two sites house several offices of the Federal Aviation Administration and the Transportation Department's Enterprise Service Center, respectively).
Oklahoma City is on the I-35 Corridor, which is one of the primary travel corridors south into neighboring Texas and Mexico and north towards Wichita and Kansas City. Located in the state's Frontier Country region, the city's northeast section lies in an ecological region known as the Cross Timbers. The city was founded during the Land Run of 1889, and grew to a population of over 10,000 within hours of its founding. The city was the scene of the April 19, 1995 bombing of the Alfred P. Murrah Federal Building, in which 168 people died. It was the deadliest terror attack in the history of the United States until the attacks of September 11, 2001, and remains the deadliest act of domestic terrorism in U.S. history.
Since the time weather records have been kept, Oklahoma City has been struck by thirteen strong tornadoes; eleven of these tornadoes were rated F4 or EF4 on the Fujita and Enhanced Fujita scales, and two were rated F5 or EF5.