I am teaching Oklahoma History this year for the first time, and it seems to be a pet project of one the parents of my students. She seems convinced that it proves that the Vikings explored Oklahoma. I am skeptical of those claims, but since I had never heard of it until she mentioned it, I thought I would ask the fine historians here what they thought, especially since this subreddit always provides sources that are more trustworthy than just "Wikipedia says it's probably a hoax."
A number of purported rune stones exist in Oklahoma. In this paper each stone is physically examined, linguistically analyzed, and compared with Norse predecessors to determine if there is any evidence of them being of Viking origin.First documented in 1923, the Heavener Rune Stone is the earliest known inscription. The veracity of the Heavener stoneas a Viking artifact is problematic. The linguistic evidence is ambiguous. However, historical evidence from the 19th century covering both the Viking Revival, Scandinavian immigration, and the lack of archaeological evidence of Norseexcursions to the Western US, strongly suggests the stone is a 19 thcreation of a Scandinavian immigrant (likely a Swedish immigrant working at the local train depot). The Shawnee and Pawnee stones can be shown via linguistic and physical evidence to be modern creations. Heavener Rune Stones Two and Three are much earlier and are most likely of non-runic Native American creation.
http://www.academia.edu/2332282/An_Archaeologist_Looks_at_the_Oklahoma_Runestones_ESOP_29_2011_5-43