Camp Poplar River was established during the Indian wars in the Department of Dakota by U.S. Army to maintain order, keep non-agency Indians away, and help capture the Indians who disturbed the peace and would not conform to reservation boundaries of the Fort Peck Agency, which in 1878, was relocated to its present day location in Poplar because the original agency was located on a flood plain, suffering floods each spring. The post was located one-half mile north of the then called, Poplar River Agency, or 2 miles north of the Missouri River on the south bank of the Poplar River and normally consisted of only two companies of infantry.