range extending east-west for 200 miles (320 km) in northwestern Arkansas and northeastern Oklahoma, U.S. The highest section of the Ozark Mountains, they are bounded by the White River (which has its source there) and by the Arkansas River. Several peaks, including Turner Ward Knob and Brannon Mountain, exceed 2,400 feet (730 m). The rugged mountains, 30 to 35 miles (50 to 55 km) wide with gorgelike valleys, embrace a division of the Ozark National Forest, Buffalo National River, and Devil's Den State Park, Arkansas.