Claim: Part of the Ozarks is in Oklahoma.

The Ozarks , also referred to as the Ozark Mountains , Ozarks Mountain Country , and the Ozark Plateau , is a physiographic and geologic highland region of the central United States , primarily in Arkansas , Missouri , and Oklahoma . The Ozarks cover a significant portion of southern Missouri , extending as far northeast as the southwestern suburbs of St. Louis . In Arkansas , a large portion is contained within the northwestern and northcentral region . Much smaller pieces of the Ozarks extend westward into northeastern Oklahoma and extreme southeastern Kansas .   The Shawnee Hills of southwest Illinois , which lie near the eastern edge of this region , are commonly called the `` Illinois Ozarks , '' but are generally not considered part of the true Ozarks .   Although sometimes referred to as the Ozark Mountains , the region is actually a high and deeply dissected plateau . Geologically , the area is a broad dome around the Saint Francois Mountains . The Ozark Highlands area , covering nearly 47000 sqmi , is by far the most extensive mountainous region between the Appalachians and the Rocky Mountains . Together , the Ozarks and Ouachita Mountains form an area known as the U.S. Interior Highlands , and are sometimes referred to collectively . For example , the ecoregion called Ozark Mountain Forests includes the Ouachita Mountains , although the Arkansas River Valley and the Ouachitas , both south of the Boston Mountains , are not usually considered part of the Ozarks .