The 7th Iowa Cavalry was mustered into Federal service at Davenport, Iowa, for a three-year enlistment between April 27 to July 13, 1863. On September 19, 1863, it was deployed to Omaha en route to the west. In 1864, three companies of the regiments were part of Lieutenant Colonel Samuel M. Pollock's 1st Brigade of Brigadier General Alfred Sully's District of Iowa. In this organization, these companies participated in the Northwestern Indian Expedition, fighting at the Battle of Killdeer Mountain and in the Battle of the Badlands. Units of the regiment were at Camp Rankin on the South Platte in January, 1865 when more than 1,000 plains Indians attacked the fort and stage station at Julesburg during the Sioux Wars following the Sand Creek Massacre. In the Battle of Julesburg, 14 men of the 7th were killed, including 4 non-commissioned officers. Company F of the regiment accompanied Colonel James H. Kidd's column of the Powder River Expedition in 1865 to the Powder and Tongue river valley's in Dakota Territory and Montana Territory.