Near Dunn Center in western North Dakota, this pre-Columbian quarry on Spring Creek was one of the major sources of Knife River flint, a stone widely used by Indigenous peoples for projectile points, knives, and scraping tools. Worked from about 11,000 B.C. to A.D. 1600, it supplied material that traveled across prehistoric North America through long-distance exchange networks, reaching places as distant as northern Canada, New York, and New Mexico. Covering at least 690 acres and containing an estimated 20,000 quarry pits, the site preserves striking evidence of centuries of extraction and toolmaking and offers important insight into prehistoric technology and trade.