Oklahoma has four primary mountain ranges: the Ouachita Mountains, the Arbuckle Mountains, the Wichita Mountains, and the Ozark Mountains. Contained within the U.S. Interior Highlands region, <answer>the Ozark and Ouachita Mountains</answer> mark the only major mountainous region between the Rocky Mountains and the Appalachians. A portion of the Flint Hills stretches into north-central Oklahoma, and near the state's eastern border, Cavanal Hill is regarded by the Oklahoma Tourism & Recreation Department as the world's tallest hill; at 1,999 feet (609 m), it fails their definition of a mountain by one foot.
Which of Oklahoma's mountain ranges are in the US Interior Highlands?
the Ozark and Ouachita Mountains