Battery E of the 2nd United States Artillery was referenced on a War Department marker at Antietam.

1861
January At Washington, D. C.
June Attached to Schenck’s Brigade, Tyler’s Division, McDowell’s Army, Northeast Virginia
July 16-21 Advance on Manassas, Va.
July 17 Occupation of Fairfax Court House
July 21
Battle of Bull Run
August Duty in the Defenses of Washington attached to Artillery, Army of the Potomac
October Assigned to Porter’s Division, Army of the Potomac
1862
March Assigned to Artillery Reserve, Army of the Potomac and moved to the Virginia Peninsula.
April 5-May 4 Siege of Yorktown
May 4 Near Williamsburg
May Attached to 5th Brigade, Artillery Reserve, 5th Army Corps, Army of the Potomac
June 25-July 1 Seven days before Richmond
June 30 Turkey Bridge
July 1
Malvern Hill
July At Harrison’s Landing
August 16-28 Movement to Centreville, Va.
August 29
Battle of Groveton
August 30
Second Battle of Bull Run
September 1
Chantilly
September 6-22 Maryland Campaign. Attached to Artillery, 1st Division, 9th Army Corps
September 14
Battle of South Mountain

From Lieutenant Benjamin’s official report:

The battery was ordered to report to General Pleasonton at about 8 a. m. After reporting, it was placed in position to the left of the turnpike, on a high knoll, commanding a portion of the pass. We engaged three batteries in the course of the day, one on a knoll to the right of the turnpike, about 2,600 yards from us, the others on the right and left of the pike on the hills. The first two commanded our position, the third we commanded. The first we silenced twice, after which it did not open again. The second and third we fired at to draw the fire from our infantry. We also shelled the wood in several places, and shelled a column far up the pass, apparently with some effect. A detachment of the Seventy-ninth New York Volunteers, temporarily attached to the battery, did their duty well throughout the day. The officers, non-commissioned officers, and privates all behaved well. We had no casualties, no projectiles of any kind coming near us.

September 16-17
Battle of Antietam

Battery E was commanded by Lieutenant Samuel H. Benjamin. It brought 93 men to the field and was armed with four 20-pounder Parrotts.

From the War Department marker on the Antietam battlefield:

On the morning of September 16, Benjamin’s Battery took position on the ridge bordering the Antietam above the Burnside Bridge, engaged the Confederate Batteries on and around the Cemetery Hill, and shelled the infantry north of Sharpsburg. In the afternoon the Battery moved to the left (south) and rear on the high ground about 1950 yards east of this point. Early in the morning of the 17th, it opened fire upon and quickly silenced a Confederate Battery which was shelling Rodman’s Division. It engaged batteries posted on Cemetery Hill and high ground adjacent and, several times during the day, shelled bodies of infantry. At 3 P.M., the Battery changed position to the left in order to shell A. P. Hill’s Division as it came upon the field. Its last six rounds of ammunition were used in engaging some heavy guns on the Confederate left.

From Lieutenant Benjamin’s official report:

On the 16th instant, on being ordered to the front at about 9 o’clock, the battery was placed in position by Lieutenant-Colonel Getty, Fifth U. S. Artillery. After firing a few shots at bodies of the enemy, we opened on a brigade marching in column toward our right, and soon drove them in confusion into a ravine.

At about 10.30 a. m. the enemy opened fire on us, and on some heavy guns some distance on our right, with ten or twelve pieces. We returned fire, the batteries on the right also returning it, and in about an hour the enemy’s batteries were silenced. In the afternoon we changed position, taking position on a knoll some distance to the left, and back from the stone bridge.

On the morning of the 17th we opened fire early on a battery which was shelling General Rodman’s division, soon silencing it. Several times during the day we engaged a battery of eight guns to the right of Sharpsburg, each time driving the cannoneers from their guns. We also fired on batteries to the left of the town, to draw their fire from our infantry.

After the firing on the 16th instant I replenished my caissons, and on the morning of the 17th I sent for ammunition, but only received 40 rounds, being all that there was on the train. The battery changed position at about 3 p. m., in order to fire more to the left. Several times in the course of the day we shelled bodies of rebel infantry. At about 5 or 5.30 p. m., the enemy opened with some very heavy guns from their left. I fired my last six rounds at them. After my ammunition was exhausted I remained in position some time.

Two of my horses being killed by their shell, I returned to my first position in order to cover my horses, and, by order of General Burnside, fired blank cartridges to draw the enemy’s fire from our infantry.

The men attached to the battery behaved well. Sergeants Keefe, Kaiser, and Ferris, and Corporal Eidleman, managed their guns and detachments well. My officers, Lieutenants Graves and Lord, worked well and faithfully. A detachment of the Seventy-ninth New York Volunteers, temporarily attached to the battery, did their duty coolly and well. On the 16th the firing of the enemy for some time was pretty sharp, but no one was injured. On the 17th we were fired at but little, and without effect, except two horses killed. Private Drimer was accidentally wounded in the hand by a piece of friction-primer. Two guns became unserviceable from the vent-pieces wearing out.

November 15 Warrenton or Sulphur Springs
December Attached to Artillery, 3rd Division, 9th Army Corps
December 12-15
Battle of Fredericksburg
1863
January 20-24 “Mud March”
February 10 Moved to Newport News and duty there attached to Artillery, 1st Division, 9th Army Corps, Army of the Potomac
March 19-23 Movement to Kentucky
March 24 Duty in District of Central Kentucky attached to Dept. of the Ohio
June 7-14 Moved to Vicks burg, Miss. and attached to Artillery Reserve, 9th Army Corps, Dept. of the Ohio
June 14-July 4 Siege of Vicksburg
July 4-10 Advance on Jackson, Miss.
July 10-17 Siege of Jackson
August 4-18 Moved to Covington, thence to Crab Orchard, Ky. Attached to Artillery, 1st Division, 9th Army Corps, Dept. of the Ohio
September 10-26 March to Knoxville, Tenn.
November 4-December 23 Knoxville Campaign
November 16 Action at Campbell’s Station
November 17-December 5 Siege of Knoxville
November 29 Repulse of Longstreet’s assault on Fort Saunders
December-March Operations in East Tennessee
1864
March Attached to Reserve Artillery, 9th Army Corps, Army of the Potomac
April Ordered to Annapolis, Md.
May 4-June 7 Rapidan (Va.) Campaign
May 5-7
Battle of the Wilderness
May 8-21
Battle of Spotsylvania
May 28-31 Totopotomoy
June 1-7
Cold Harbor
June 1-3 Bethesda Church
June Ordered to Washington, D. C., and duty in the Defenses of that city attached to Camp Barry, 22nd Army Corps
August 24 Consolidated with Battery C 2nd Artillery and attached to 1st Separate Brigade, 22nd Army Corps until October 1865