Oklahoma 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 the choicest pieces of land before the official opening date and the Indian Appropriations Act of 1889, which opened the door for white settlement in America's Indian Territory. The name was settled upon statehood. 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 "Okies", and its capital and largest city is Oklahoma City.
With small mountain ranges, prairie, mesas, and eastern forests, most of Oklahoma lies in the Great Plains, Cross Timbers, and the U.S. Interior Highlands, a region prone mainly to severe weather. In addition to having a prevalence of English, German, Scottish, Scotch-Irish, and Native American ancestry, more than 25 Native American languages are spoken in Oklahoma, third only to Alaska and California.
Oklahoma is on a confluence of three major American cultural regions and historically served as a route for cattle drives, a destination for Southern settlers, and a government-sanctioned territory for Native Americans. The main Sioux tribe that originally inhabited the state were the Ponca.
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.