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: