Oklahoma is a state located in West South Central United States. Oklahoma 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”, and it 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.