Battery A, 2nd U.S. Artillery

Each regiment was to have one colonel, one lieutenant-colonel, one major, one supernumerary captain (for ordnance duty), one adjutant, one sergeant-major, and nine companies.

The new company was placed under the command of Captain Alexander Fanning, and was stationed on post at the U.S. Military Academy at West Point, New York.

General Winfield Scott took command of the U.S. Army forces in the area, and assigned Companies A, B, G, and H to Colonel William Lindsay's column, at Fort Brooke.

Battery A participated in the removal of the Cherokee nation from Alabama and Tennessee in 1838, as it was being reassigned to posting along the Great Lakes, also referred to as the “Niagara frontier”.

Light Battery A, under the command of First Lieutenant James Duncan, left New York Harbor in August 1845, arriving in September at Corpus Christi to join General Zachary Taylor's army.

Along with C and K, "as a part of the artillery battalion, and A were engaged at Palo Alto (May 8) and Resaca de la Palma (May 9).

Duncan by his brilliant advance and attack, without orders, on the Mexican right at Palo Alto, did much towards winning the battle and was specially mentioned by General Taylor."

The regiment took part in all the battles of the campaign, figuring most prominently and suffering the heaviest losses at Churubusco, Molino del Rey, and City of Mexico."

It was deployed temporarily to Florida, but soon returned to the Eastern Theater before the First Battle of Bull Run, and was outfitted as a horse artillery battery in September 1861.

Hays, his successor, John M. Robertson (sic), and the first commander of the 2d Horse Artillery Brigade, J. C. Tidball, were all captains of the 2d.

In the spring of 1862 it went to the Peninsula, forming, with B and L (Robertson), and M. (Benson) of the 2d and C (Gibson) of the 3d, the famous Horse Artillery Brigade.

At Yorktown during the siege it was in pursuit with Stoneman's cavalry after the evacuation, and was engaged at Williamsburg, New Bridge, and Mechanicsville.

While at Harrison's Landing a corporal died, and permission to fire the usual salute being refused, it occurred to Capt.

The battery was out with Averell's cavalry in April, 1863, and was engaged at Rapidan Station, May 1, and with Pleasanton at Upperville, June 20.

In the campaign of 1864 the battery was engaged at Cold Harbor, Bottom's Bridge, Trevilian Station, and St. Mary's Church.

While with the army before Petersburg it was several times detached on expeditions with the cavalry, being engaged at Deep Bottom, July 28, Lee's Mill, July 31, Deep Run, August 16, Vaughn Plank Road, September 29, Boydton Plank Road, October 27, Stoney Creek, December 1, and on the Weldon Railroad, December 7–11.

Battery A returned to Fort McHenry after the war, and was later assigned to West Coast posts in California.

Only temporarily assigned to the West during the Plains Indian Wars, in 1869, its primary duties were in the East.