Battery I is referenced on a War Department marker at Antietam and honored by a monument at Gettysburg.

1861
January Stationed at Fort Leavenworth, Kan.
January 7-29 Moved to Washington, D.C.
July Attached to Wilcox’s Brigade, Heintzelman’s Division, McDowell’s Army Northeastern Virginia
July 16-21 Advance on Manassas, Va.
July 21
Battle of Bull Run
August 7-15 Moved to Poolesville, Md.
August-March Duty at Poolesville and at Edward’s Ferry attached to Stone’s Brigade, Division Potomac
October 21
Ball’s Bluff
October 22 Edward’s Ferry
October Attached to Stone’s (Sedgwick’s) Division, Army Potomac
1862
March Ordered to the Virginia Peninsula and attached to Artillery, 2nd Division, 2nd Army Corps, Army Potomac
April 5-May 4 Siege of Yorktown
May 31-June 1
Battle of Fair Oaks, Seven Pines
June 25-July 1 Seven days before Richmond
July 29
Peach Orchard and Savage Station
June 30
White Oak Swamp and Glendale
July 1
Malvern Hill
August 16-23 Moved to Alexandria, Va.
September 6-22 Maryland Campaign
September 16-17
Battle of Antietam

The battery was commanded by Lieutenant George A. Woodruff.

From the marker on the Antietam battlefield:

Between 9 and 10 A.M., Battery I, 1st Artillery, advancing by the Smoketown Road, passed through the East Woods to the assistance of the Infantry of Sedgwick’s Division, then engaged in the West Woods. The Battery went into position about 380 yards north, 62° west of this point, opening fire at once, with canister, and checking the advance of the Confederates from the West Woods. A movement of the enemy on its left, from the woods around the Dunkard Church, compelled the Battery to retire to this point, its left gun on the road, where it again went into action. It remained in this position until about noon, when it was relieved by Batteries A and C (consolidated), 4th U.S. Artillery, and withdrawn. At 5 P.M., after replenishing ammunition, the Battery took position on the ground overlooking the Sunken Road where Richardson’s Division had been engaged, and remained until 2 P.M. of the 18th.

September 18 At Harper’s Ferry
October 30-November 17 Movement to Falmouth, Va.
November Assigned to Reserve Artillery, 2nd Army Corps
December 11-15 Battle of Fredericksburg
1863
January 20-24 “Mud March”
February-April At Falmouth
April 27-May 6 Chancellorsville Campaign
May 1-5
Battle of Chancellorsville
May Assigned to Artillery Brigade, 2nd Army Corps
June 11-July 24 Gettysburg Campaign
July 1-3
Battle of Gettysburg

From the monument:

Battery I First U.S. Artillery,
Six 12 Pounders, Lieut. George A. Woodruff commanding, Lieut. Tully McCrea commanding.

July 2&3 Arrived and took position in Ziegler’s Grove on the left of Evergreen Cemetery. Actively engaged and assisted in repelling Longstreet’s Assault. Lieut. Woodruff was mortally wounded on the 3d and the command devolved on Lieut. Tully McCrea.

Casualties: killed 1 man, wounded 1 officer and 28 men

September 13-17 Advance to line of the Rapidan
October 9-22 Bristoe Campaign
October 14 Bristoe Station
November 7-8 Advance to line of the Rappahannock
November Assigned to 2nd Brigade, Horse Artillery, Artillery Reserve, Army of the Potomac
November 26-December 2 Mine Run Campaign
1864
May Campaign from the Rapidan to the James.
May 5-7
Battle of the Wilderness
May 8-21
Spotsylvania Court House
May 23-26 North Anna River
May 28-31 Totopotomoy
June 1-7
Cold Harbor
June 2 Gaines’ Mill, Salem Church and Haw’s Shop
June 7-24 Sheridan’s Trevillian Raid
June 11-12
Trevillian Station
June 21 Black Creek or Tunstall Station and White House or St. Peter’s Church
June 24 St. Mary’s Church
June 29-July 27 At Light House Point
August At Camp Barry, D.C.
September 29 Arthur’s Swamp
September 29-October 1 Poplar Springs Church
October 1 Wyatt’s Road
October 27-28 Boydton Plank Road
December 7-12 Warren’s Raid on Weldon Railroad
1865
February 5-7 Dabney’s Mills
March 28-April 9 Appomattox Campaign
March 30-31 Dinwiddie Court House
April 1
Five Forks
April 3 Namozine Church
April 5 Paine’s Cross Roads
April 6 Sailor’s Creek
April 9
Appomattox Court House

Surrender of Lee and his army.

May Moved to Washington, D. C.
May 23 Grand Review