On October 22, 1804, Clark observed that the expedition passed “an old Village on the S. S. and the upper of the 6 Villages the Mandans occupied about 25 years ago this village was entirely cut off by the Sioux & one of the others nearly, the Small Pox distroyed great Numbers.” The abandoned site documented by Clark – now known as Double Ditch – was another ancient Mandan earthlodge village that had been occupied for nearly 300 years until the ravages of the 1781-1782 smallpox epidemic. Although called Double Ditch, the site actually features evidence of four concentric ditches. The ditches were part of defensive perimeters. The earliest settlement, established circa 1350 CE, is estimated to have contained about 160 lodges and 2,000 families. It occupied an approximately 22-acre area. As the population subsequently diminished, the village contracted and smaller defensive perimeters were built. The fourth and final settlement at Double Ditch – established sometime in the 1700s – was reduced to only about four acres in size.
The Double Ditch Historic Site is located along the east bank of the Missouri River about seven-and-a-half miles north of Bismarck. It is publicly accessible, featuring walkways and interpretive signage. The archeo-logical remains of earthlodges, refuse mounds, and fortification ditches are clearly discernable.