By 1858 the Dakota had only a small strip of land in Minnesota. Without access to the land upon which they had hunted for generations, they had to rely on treaty payments for their survival. The inadequate money and goods often arrived late. In 1862 the Dakota were starving. This was one cause of the 1862 war between the Dakota and white soldiers. After six weeks, the war ended. Almost 400 Dakota men were tried by a military commission, and 303 were sentenced to die. President Lincoln pardoned many, but 38 Dakota men were hanged in Mankato. The Dakota were sent to prison in Iowa or to reservations at Crow Creek, in what is now South Dakota, and Santee in Nebraska Territory.

In 1863 the Dakota were forced to give up all their remaining land in Minnesota. The U.S. government canceled all treaties made with the Dakota. The Ojibwe reluctantly ceded most of their remaining land in northwestern Minnesota in treaties of 1863, 1864, and 1867. In 1871 Congress ended the practice of making treaties with Indian nations. However, past treaties remained in place.