The last settlement at Double Ditch was protected by Ditch 1, an inner fortification ditch built in the Mandan practice of surrounding villages with ditches and wooden palisades while also using steep terrain and riverbanks for added defense. Based on the 1905 archaeological excavations, the inner ditch may have been up to twenty feet wide and nine feet deep, with a flat bottom. This final village covered four acres, only about one-fifth of its original area, and its tiny bastions were much smaller than those used in Ditch 4 three hundred years earlier. Only 32 clear earthlodge depressions can be counted inside Ditch 1, indicating a population of less than 400 persons when smallpox struck in AD 1781-1782. Mounds and ruins from earlier times surrounded and towered over the small community, and intersecting pits in the village core show three centuries of continuous occupation. Few, if any, superimposed house floors or architectural features remain except from the very last cycle of lodge building, because lodge remains were completely removed before rebuilding, leaving undisturbed subsoil directly below the house floor.