The 1st U.S.V.I. was recruited at Point Lookout prison camp between January 21 and April 22, 1864, as a three-year regiment. Assigned to the District of Eastern Virginia, Department of Virginia and North Carolina, it moved to Norfolk, Virginia, where on orders of General Grant it was relegated to provost duty there, Portsmouth, Virginia, and Elizabeth City, North Carolina. In August 1864, Grant ordered it to the Department of the Northwest in Milwaukee, Wisconsin. The 1st U.S.V.I. traveled by ship to New York City, and by train to Chicago, where it received further orders splitting the regiment. Four companies continued to Milwaukee, while six companies (B, C, D, E, H, and K) were sent to St. Louis, Missouri, arriving there August 22. They moved by the steamboat "Effie Deans" and by forced march to Fort Rice, Dakota Territory, arriving there October 17 for garrison duty. Conditions were hard over the winter, and fully 11% of the command died of illness, primarily scurvy. Between May 10 and August 31, 1865, Company K garrisoned Fort Berthold and Company B the trading post known as Fort Union at the mouth of the Yellowstone, obliged to travel by steamboat through hostile territory. Four companies were present at Fort Rice, along with two companies of the 4th U.S.V.I., when a large force of Lakota and Cheyenne led by Sitting Bull attacked for three hours on July 28, 1865, making away with the entire horse herd and killing two soldiers. In October 1865, the battalion returned to St. Louis to muster out November 27.