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.klahoma is the 20th-largest state in the United States, covering an area of 69,898 square miles (181,035 km 2), with 68,667 square miles (177847 km 2) of land and 1,281 square miles (3,188 km 2) of water.