- Osage Hills: The Osage Hills is an area of low mountainous terrain in northeastern Oklahoma. The highest peak in the Osage Hills is Black Mesa, which rises 2,240 feet above sea level.
- Ozark Plateau: The Ozark Plateau is an area of rolling hills and plateaus in eastern Oklahoma. The highest point in the Ozark Plateau is Cavanal Hill, which rises 2,665 feet above sea level.
- Wichita Mountains: The Wichita Mountains are a range of mountains in southwestern Oklahoma. The highest point in the Wichita Mountains is Mount Scott, which rises 2,487 feet above sea level.
- Arbuckle Mountains: The Arbuckle Mountains are a range of mountains in south-central Oklahoma. The highest point in the Arbuckle Mountains is West Arbuckle Mountain, which rises 1,999 feet above sea level.
- Red River Valley: The Red River Valley is a wide, flat valley that runs along the border between Oklahoma and Texas. The Red River Valley is home to some of the most fertile soil in the United States.
- High Plains: The High Plains is a large area of flat, arid land in western Oklahoma. The High Plains is home to some of the largest wheat fields in the United States.