Heavener OK has a Runestone. It was apparently carved by Vikings hundreds of years before Columbus sailed. The interpretations vary. The date 11-Nov-1012 was an early interpretation. GLOMEDAL (Valley of Glome) is the more recently accepted interpretation, with an estimated carving date before 900AD. Other Runestones have been found in the area. A book called In Plain Site has other examples.
If you are in Eastern Oklahoma, stop in Heavener and see what may be the oldest carving in the United States that was not carved by a Native American.
One of the best full hook up campsites we have stayed at is a National Forest Service Campground near Heavener OK at Cedar Lake.