U.S. Horse Artillery Brigade

These mobile artillery units were typically equipped with 3-inch Ordnance rifles, known for their reliability and accuracy.

Originally under the direct command of Lt. Col. (and future Brigadier General) William Hays, and later under the two-brigade command of captains James Madison Robertson and John C. Tidball, the Horse Artillery served with distinction during most of the major engagements in the Eastern Theater.

It is notable that each of these men - Barry, Hays, Robertson, and Tidball - came from the officers corps of the 2nd Regiment of Artillery.

One of their chief champions, Henry Jackson Hunt, commanded the Reserve Artillery in the Army of the Potomac, and was also an officer of the 2nd U.S.

Artillery Commander: First Lieutenant (Brevet Major) Edward Bancroft Williston, USA Battery M, 2nd U.S.

Artillery Commander: First Lieutenant (Brevet Major) Alexander Cummings McWhorter Pennington, Jr., USA Battery A, 4th U.S.

Artillery Commander: Captain (Brevet Lieutenant Colonel) William Montrose Graham, USA Battery A, 2nd U.S.

(Benjamin Franklin) Littlefield, USV (former US Sharpshooter, on TDY from 4th New York Heavy Artillery) Battery G, 2nd U.S.

Artillery Commander: First Lieutenant (Brevet Major) John Hartwell Butler, USA Battery C, 3rd U.S.

Artillery Commander: First Lieutenant (Brevet Major) William Neil Dennison, USA Battery A, 4th U.S.