The Department of the Platte was a military administrative district established by the U.S. Army on March 5, 1866, with boundaries encompassing Iowa, Nebraska, Dakota Territory, Utah Territory and a small portion of Idaho. With headquarters in Omaha, the district commander oversaw the army's role initially along the Overland route (or Oregon Trail) to Salt Lake City, then later the construction route of the Union Pacific Railroad. The district also included the Montana road (or Bozeman Trail) through eastern Wyoming. The district was discontinued when the Army's command was reorganized in 1898.

Headquarters

The Headquarters of the Department of the Platte was located in downtown Omaha, Nebraska for many years. When the headquarters was transferred to Fort Omaha in 1878, the building it was located in was found unsuitable, and the headquarters were again transferred downtown.

Department commanders

Camps, forts and posts

Idaho Territory and Idaho

Nebraska Territory and Nebraska

Utah Territory and Utah

Wyoming Territory and Wyoming

(Wyoming Territory was transferred from the Department of Dakota on July 25, 1868)