a southern central state of the US. It is also called the Sooner State and people from Oklahoma are called Sooners. The capital and largest city is Oklahoma City. The area was part of the Louisiana Purchase, and the Five Civilized Tribes were forced to settle there in the 19th century. Oklahoma became a state in 1907. It produces oil, gas, minerals, wheat and cotton. Its places of interest include the Cherokee Cultural Center at Tahlequah and the National Cowboy Hall of Fame at Oklahoma City.