The 17th Indiana Infantry Regiment, also known as 17th Indiana Mounted Infantry Regiment, was an infantry and mounted infantry regiment that served in the Union Army from 1863 to 1865 during the American Civil War. It served in West Virginia before being transferred to the Western Theater. In that theater, it was known for its membership in the "Lightning Brigade."

The Lightning Brigade, also known as Wilder's Brigade or the Hatchet Brigade was a mounted infantry brigade from the American Civil War in the Union Army of the Cumberland from March 8, 1863, through November 1863. A novel unit for the U.S. Army, its regiments were nominally the 1st Brigade of Maj. Gen. Joseph J. Reynolds' 4th Division of Thomas' XIV Corps. Operationally, they were detached from the division and served as a mobile mounted infantry to support any of the army's corps. Colonel John T. Wilder was its commander. As initially organized, the brigade had the following regiments:92nd Illinois Mounted Infantry: Col. Smith D. Atkins 98th Illinois Mounted Infantry: Col. John J. Funkhouser (w), Lt. Col. Edward Kitchell 123rd Illinois Mounted Infantry: Col. James Monroe 17th Indiana Mounted Infantry: Maj. William T. Jones 72nd Indiana Mounted Infantry: Col. Abram O. Miller 18th Independent Battery Indiana Light Artillery: Capt. Eli Lilly