United States Regiments & Batteries > Pennsylvania


The 100th Pennsylvania Volunteer Infantry Regiment lost 16 officers and 208 enlisted men killed or mortally wounded and 2 officers and 183 enlisted men to disease during the Civil War. The regiment is honored by a monument on the Antietam battlefield.

August 31 Organized at Pittsburg. Recruited in Lawrence, Washington, Butler, Beaver, Mercer and Westmoreland Counties.
September 2 Left State for Washington, D.C. Attached to Casey’s Provisional Division
October 9 Moved to Annapolis, Md. Attached to Stevens’ 2nd Brigade, Sherman’s South Carolina Expedition. Captain David Leckey of Company M was promoted to major.
October 21-November 7 Sherman’s Expedition to Port Royal Harbor, South Carolina, attached to 2nd Brigade, 2nd Division, Dept. of the South
November 7 Capture of Forts Walker and Beauregard, Port Royal Harbor
December 8 Occupation of Beaufort, S.C.
January 1 Port Royal Ferry, Coosa River
June 1-28 Operations on James Island, S.C.
June 3 Legaire’s Point, James Island
June 3-4 Skirmishes on James Island
June 16 Battle of Secessionville, James Island
June 28-July 7 Evacuation of James Island and movement to Hilton Head, S.C.
July 12-17 Moved to Newport News, Va. and attached to 2nd Brigade, 1st Division, 9th Army Corps, Army Potomac. Mejor Leckey was promoted to lieutenant colonel.
August 4-6 To Fredericksburg
August 6-16 Operations in support of Pope
August 16-September 2 Pope’s Campaign in Northern Virginia
August 29
Battle of Groveton
August 30
Second Battle of Bull Run
September 1
Battle of Chantilly
September 6-24 Maryland Campaign Attached to 3rd Brigade, 1st Division, 9th Army Corps
September 14
Battle of South Mountain

The regiment lost 9 men killed and 25 wounded.

September 16-17
Battle of Antietam

The 100th Pennsylvania was comanded at the Battle of Antietam by Lieutenant Colonel David A. Leckey. Assigned as skirmishers for the brigade, it suffered 7 enlisted men wounded and one man missing in its advance from Antietam Creek to the edge of Sharpsburg.

From the War Department tablet for Welsh’s Brigade on the Antietam battlefield:

On the morning of the 17th Welsh’s Brigade was in reserve on the eastern slope of the ridge on the left bank of the Antietam, nearly opposite the Burnside Bridge. About 2 P.M., after Sturgis’ Division had carried the bridge, the Brigade crossed and, following the road to Sharpsburg about 250 yards, formed line west of the road.

The Brigade then advanced over the high ground west of the road, gradually crossing to the east, until its right was near this point, its center in the ravine and at the stone mill, and its left in the apple orchard beyond, when the attack of A.P. Hill on the left flank of the Corps compelled it to withdraw to the banks of the Antietam, where it remained until the evening of the 18th.

October 11-November 18 March up the Potomac to Leesburg, then to Falmouth
December 12-15
Battle of Fredericksburg
December 30
Lieutenant Colonel Leckey resigned.
January 20-24 Burnside’s 2nd Campaign, “Mud March”
February 13 Moved to Newport News, Va.
March 20-28 To Covington, Ky.
April Duty in District of Kentucky at Paris, Nicholasville, Lancaster, Stanford and Somerset attached to 3rd Brigade, 1st Division, 9th Army Corps, Dept. Ohio
June 4-10 Movement through Kentucky to Cairo, Ill.
June 14-17 To Vicksburg, Miss.
June 17-July 4 Siege of Vicksburg Attached to Army of the Tennessee
July 5-10 Advance on Jackson, Miss.
July 10-17 Siege of Jackson
July Duty at Milldale
August 6 Moved to Covington, Ky. and attached to the Army of the Ohio
August 6-18 To Crab Orchard, Ky.,
September 10-26 March to Knoxville, Tenn.
October 10 Action at Blue Springs
November 4-December 23 Knoxville Campaign
November 16 Campbell Station
November 17-December 4 Siege of Knoxville
November 29 Repulse of Longstreet’s assault on Fort Saunders
December 5-24 Pursuit of Longstreet
December 25 At Blain’s Cross Roads
January Veterans marched over Cumberland Mountains to Nicholasville, Ky. and on furlough until March.
April Ordered to Annapolis, Md., and duty there attached to 2nd Brigade, 1st Division, 9th Army Corps, Army Potomac
May 4-June 12 Rapidan Campaign. Attached to 1st Brigade, 1st Division, 9th Army Corps
May 5-7
Battle of the Wilderness
May 8-21
Battle of Spotsylvania Court House
May 10 Ny River
May 12 Assault on the Salient
May 12-21 North Anna River
May 24 Ox Ford
May 26-28 Line of the Pamunkey
May 28-31 Totopotomoy
June 1-12
Cold Harbor
June 1-3 Bethesda Church
June 16-18 First Assault on Petersburg
June 16, 1864 -April 2, 1865 Siege of Petersburg
July 30 Mine Explosion, Petersburg
August 18-21 Weldon Railroad
September Attached to 3rd Brigade, 1st Division, 9th Army Corps
September 29-October 2 Poplar Springs Church
November 8 Reconnaissance on Vaughan and Squirrel Level Road
October 27-28 Boydton Plank Road, Hatcher’s Run
March 25 Fort Stedman
March 28-April 9 Appomattox Campaign
April 2 Final assault on Petersburg
April 3 Occupation of Petersburg
April 3-8 Pursuit of Lee
April 21-28 Moved to Washington, D. C
May 23 Grand Review
July 24 Mustered out