Oklahoma ( ) is a state located in the South Central region of the United States of America. With an estimated 3,617,316 residents in 2007 and a land area of 68,667 square miles (177,847 km²), Oklahoma is the 28th most populous and 20th-largest state. The state's name is derived from the Choctaw words okla and humma, meaning "red people", and is known informally by its nickname, The Sooner State. Formed by the combination of Oklahoma Territory and Indian Territory on November 16, 1907, Oklahoma was the 46th state to enter the union. Its residents are known as Oklahomans, and its capital and largest city is Oklahoma City. It is one of only two states that share its name with its capital city.

A major producer of natural gas, oil and agriculture, Oklahoma relies on an economic base of aviation, energy, telecommunications, and biotechnology. It has one of the fastest growing economies in the nation, ranking among the top states in per capita income growth and gross domestic product growth. Oklahoma City and Tulsa serve as Oklahoma's primary economic anchors, with nearly 60 percent of Oklahomans living in their metropolitan statistical areas. The state holds a mixed record in education and healthcare, and its largest universities participate in the NCAA and NAIA athletic associations, with two collegiate athletic departments rated among the most successful in American history.

With small mountain ranges, prairie, and eastern forests, most of Oklahoma lies in the Great Plains and the U.S. Interior Highlands—a region especially prone to severe weather. In addition to having a prevalence of German, Irish, British and Native American ancestry, more than 25 Native American languages are spoken in Oklahoma, the most of any state. It is located 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. Part of the Bible Belt, widespread belief in evangelical Christianity makes it one of the most politically conservative states, though Oklahoma has more voters registered in the Democratic Party than in any other party.

Etymology

The name Oklahoma comes from the Choctaw phrase okla homma, literally meaning red people. Choctaw Chief Allen Wright suggested the name in 1866 during treaty negotiations with the federal government regarding the use of Indian Territory, in which he envisioned an all-Indian state controlled by the United States Superintendent of Indian Affairs. Equivalent to the English word Indian, okla humma was a phrase in the Choctaw language used to describe the Native American race as a whole. Oklahoma later became the de facto name for Oklahoma Territory, and it was officially approved in 1890, two years after the area was opened to white settlers.