<Tr> <Td_colspan="2"> Released in 2008 </Td> </Tr> <Tr> <Td_colspan="2"> Lists of United States state symbols </Td> </Tr> <P> Oklahoma (/ ˌoʊkləˈhoʊmə / (listen); Pawnee: Uukuhuúwa, Cayuga: Gahnawiyoˀgeh) is a state in the South Central region of the United States . It is the 20th-most extensive and the 28th-most populous of the 50 United States . The state's name is derived from the Choctaw words okla and humma, meaning "red people ." It is also known informally by its nickname, "The Sooner State," in reference to the non-Native settlers who staked their claims on land before the official opening date and the Indian Appropriations Act of 1889, which dramatically increased European - American settlement in the Indian Territory . Oklahoma Territory and Indian Territory were merged and Indian was dropped from the name . On November 16, 1907, Oklahoma became the 46th state to enter the union . Its residents are known as Oklahomans, or informally as Okies, and its capital and largest city is Oklahoma City . </P> <P> A major producer of natural gas, oil, and agricultural products, Oklahoma relies on an economic base of aviation, energy, telecommunications, and biotechnology . In 2007, it had one of the fastest - growing economies in the United States, ranking among the top states in per capita income growth and gross domestic product growth . Both Oklahoma City and Tulsa serve as Oklahoma's primary economic anchors, with nearly two - thirds of Oklahomans living within their metropolitan statistical areas . </P>

What part of the country is oklahoma considered