In 1947, construction on the Garrison Dam began. A part of the Missouri River Basin Project, the dam would result in the creation of Lake Sakakawea and the taking of communities, farms, and businesses through eminent domain. Approximately 80 percent of the tribal members lived in soon to be flooded areas, and were forced to relocate. This area represented 25 percent of the reservation, and provided the most fertile farming areas.

The acquisition of the land was questionable at best; the US government offered $5,105,652 for land independently appraised at $21,981,000. After lengthy opposition, eventually the House and the Senate compromised at $7,500,000 to cover all relocation and reconstruction costs. However, former landowners were unable to maintain grazing and pasture rights, fishing and hunting rights, or mineral rights.

The relocation uprooted homes and businesses, families and farms. Worried about having promised lands taken once again, ten members of tribal leadership traveled to Washington DC to try and stop the development. The wheels were already in motion though, and construction on the dam was progressing even before the negotiations for compensation were finished.