Missouri is a state in the Midwestern United States. With over six million residents, it is the 18th-most populous state of the Union. The largest urban areas are Kansas City, St. Louis, Springfield, and Columbia the capital is Jefferson City, located on the Missouri River. The state is the 21st-most extensive in area. In the South are the Ozarks, a forested highland, providing timber, minerals, and recreation. The Mississippi River forms the eastern border of the state.