The Rimrock Draw Rockshelter Site, Rewriting the Archaeological Record

In the high desert of eastern Oregon, a quiet revolution in our understanding of early human history is unfolding. At Rimrock Draw Rockshelter, archaeologist Dr. Patrick O'Grady/Burns Bureau of Land Management and his team have unearthed compelling evidence that humans occupied this site over 18,000 years ago, potentially making it one of the oldest known human habitation sites in North America. Among the remarkable discoveries are finely crafted stone tools, including scrapers made of chalcedony, one of which still bore traces of bison blood. These tools were found beneath layers of volcanic ash from a Mount St. Helens eruption dated to 15,300 to15,600 years ago, suggesting the artifacts are even older. Further excavation revealed tooth fragments from extinct Pleistocene mammals like camels and bison. Radiocarbon dating of these remains yielded dates as old as 18,300 years before present.

This Chalcedony multi-tool might be the oldest lithic artifact in the Americas

This chalcedony tool still had bison residue on it, and was found below the 15,000 year old volcanic ash layer, and also below the layer that contained camel tooth enamel dating to 18,300 years ago. It was knapped for work, with two scraper edges and a bifacial edge with high polish.

The ongoing work at Rimrock Draw Rockshelter not only pushes back the timeline of human presence in North America but also enriches our understanding of early human life and migration. As Dr. O'Grady and his team continue their meticulous excavation, each artifact adds a new chapter to the story of our ancient ancestors.

To preserve and share these significant finds, five artifacts have been entrusted to OccPaleo for molding and casting. These casts will be available in our store.

For more detailed information about the Rimrock Rockshelter site, a presentation given by Dr. O'Grady to the Pacific Coast Archaeological Society (PCAS) on May 9, 2024, is linked below.