The Dakota non-combatants arrived at Fort Snelling on November 13, 1862, and encamped on the bluff of the Minnesota River about a mile west of the fort. Shortly after, Marshall and his soldiers moved the Dakota to the river bottom directly below the fort. In December soldiers built a concentration camp, a wooden stockade more than 12 feet high enclosing an area of two or three acres, on the river bottom. More than 1,600 Dakota people were moved inside. A warehouse just outside the camp was used as a hospital and mission station. Throughout the camp’s existence, soldiers of the Sixth, Seventh, and Tenth Minnesota Volunteer Infantry Regiments guarded the stockade, controlling movement in and out. It is estimated that between 130 and 300 Dakota people died over the winter of 1862–63, mainly due to measles, other diseases, and harsh conditions.

The concentration camp at Fort Snelling was not a death camp, and Dakota people were not systematically exterminated there. The camp was, however, a part of the genocidal policies pursued against Indigenous people throughout the US. Colonists and soldiers hunted down and killed Dakota people, abused them physically and mentally, imprisoned them, and subjected them to a campaign calculated to make them stop being Dakota.