Oklahoma is a state located in the South Central region

South Central United States

The South Central United States or South Central states is a region of the United States located in the south central part of the country. It evolved out of the archaic southwest, which originally was literally the western U.S. South...

 of the United States of America. With an estimated 3,751,351 residents as of the 2010 census 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

Choctaw

The Choctaw are a Native American people originally from the Southeastern United States...

 words okla and humma, meaning "red people", and is known informally by its nickname, The Sooner

Sooners

Sooners is the name given to settlers in the midwest of the United States who entered the Unassigned Lands in what is now the state of Oklahoma before President Grover Cleveland officially proclaimed them open to settlement on March 2, 1889 with the Indian Appropriations Act of 1889...

 State. Formed by the combination of Oklahoma Territory

Oklahoma Territory

The Territory of Oklahoma was an organized incorporated territory of the United States that existed from May 2, 1890, until November 16, 1907, when it was joined with the Indian Territory under a new constitution and admitted to the Union as the State of Oklahoma.-Organization:Oklahoma Territory's...

 and Indian Territory

Indian Territory

The Indian Territory, also known as the Indian Territories and the Indian Country, was land set aside within the United States for the settlement of American Indians...

 on November 16, 1907, Oklahoma was the 46th state to enter the union.