The Spiro site was abandoned around 1450 AD, following the decline of the Mississippian Culture. The resting place of this culture remained undisturbed for more than four hundred years.

From 1933 until 1935 a group of locals under the guise of a mining company carelessly dug into one of the burial mounds in search of treasure. This commercial digging had devastating results, causing countless artifacts and burials to be damaged or destroyed. Sadly this also led to thousands of well-preserved Spiro artifacts recklessly sold to individuals and entities around the world. Fortunately the Oklahoma Legislature put a stop to this destruction in November 1935. The following year, the University of Oklahoma began a scientific excavation of what remained at the Spiro Mounds site.