The Third Maryland Infantry Regiment lost 8 officers and 83 enlisted men killed or mortally wounded and 4 officers and 130 enlisted men to disease during the Civil War.

It is is honored by a monuments at Antietam and Gettysburg.

August –
February 16
Companies A, B, C, D and H organized at Baltimore. Attached to Dix’s Division, Baltimore, Md.
Summer 4 Companies organized at Williamsport; assigned as Companies A, B, C and I; Original Companies A, B, C and D designated Companies D, E, F and G
May 11 Companies E, F, H and I broken up and distributed among Companies A, B, C, D and G; two Companies originally recruited for 4th Maryland Infantry assigned as Companies E and H. Two Companies recruited for Dix’s Light Infantry were assigned as Companies I and K.
May 11-23 Duty at Baltimore, Md.
May 24 Moved to Harper’s Ferry, W. Va. Assigned to 1st Brigade, Sigel’s Division, Dept. of the Shenandoah
May 28-30 Defense of Harper’s Ferry
June Attached to 2nd Brigade, 2nd Division, 2nd Corps, Pope’s Army of Virginia; Operations in the Shenandoah Valley
August Attached to 1st Brigade, 2nd Division, 2nd Army Corps, Army of Virginia
August 9 Battle of Cedar Mountain
August 16-
September 2
Pope’s Campaign in Northern Virginia
August 21-23 Fords of the Rappahannock
August 24 Sulphur Springs
August 28-29 Plains of Manassas (Reserve)
August 30 Battle of Bull Run (Reserve)
September Assigned to 2nd Brigade, 2nd Division, 12th Army Corps, Army of the Potomac
September 1 Battle of Chantilly
September 6-22 Maryland Campaign
September 16-17
Battle of Antietam

The regiment was commanded by Lieutenant Colonel Joseph M. Sudsburg. It brought 148 men to the field, losing one man killed, 25 wounded, and four missing in the fighting that brought it to the corner of the Dunker Church.

September 22 – December 10 Duty at Bolivar Heights
October 15 Company F organized at Euston, Md. for 9 months
October Assigned to 2nd Brigade, 1st Division, 12th Army Corps
November 9 Reconnaissance to Rippen, W. Va.
December 2-6 Expedition to Winchester
December 10-14 Moved to Fredericksburg
December 14 At Stafford’s Court House
January 20-24 “Mud March”
April 27 Chancellorsville Campaign
May, 1863 1st Brigade, 1st Division, 12th Army Corps, Army of the Potomac
May 1-5
Battle of Chancellorsville
June 11 – July 24 Gettysburg Campaign
July 1-3
Battle of Gettysburg

The regiment was commanded by Colonel Joseph M. Sudsburg. It brought 278 men to the field, losing one man killed and seven wounded.

From the monument on Culp’s Hill at Gettysburg:

Occupied this position in reserve. Late in the afternoon moved to reinforce the left of the line, returning about 9 p.m. and finding the works occupied by the enemy.

July 3d Under fire in reserve, until about noon. Then occupied the works in front and held them until relieved. Losing in killed Capt. Henry Fenton, Company G. Wounded 1 officer and 6 men.

July 5-24 Pursuit of Lee
July – September At Raccoon Ford
September 2 Company F mustered out
September 24 –
October 4
Moved to Brandy Station, thence to Bealeton and to Stevenson, Ala.; attached to Army of the Cumberland; Guard duty on Nashville & Chattanooga Railroad
March – April Veterans on furlough March and April

Non-Veterans were assigned to the 1st Brigade, 1st Division, 20th Army Corps, Army of the Cumberland

Veterans returned from their furlough to be assigned to the 2nd Brigade, 1st Division, 9th Army Corps, Army of the Potomac

Timeline for old members in the Army of the Cumberland in the Atlanta Campaign
May 1 –
September 8
Old members participated in Atlanta Campaign
May 8-11 Demonstration on Rocky Faced Ridge
May 14-15 Battle of Resaca
May 19 Near Cassville
May 22-25 Advance on Dallas
May 25 New Hope Church
May 26-June 5 Battles about Dallas, New Hope Church and Allatoona Hills
June 10-July 2 Operations about Marietta and against Kenesaw Mountain
June 11-14 Pine Mountain
June 15-17 Lost Mountain
June 15 Gilgal or Golgotha Church
June 17 Muddy Creek
June 19 Noyes Creek
June 22 Kolb’s Farm
June 27 Assault on Kenesaw
July 4 Ruff’s Station, Smyrna Camp Ground
July 5-17 Chattahoochie River
July 19-20 Peach Tree Creek
July 22-August 25 Siege of Atlanta
August 26 –
September 2
Operations at Chattahoochie River Bridge
September 2 Occupation of Atlanta
Timeline for Veterans in the Army of the Potomac
April Regiment joined 2nd Brigade, 1st Division, 9th Army Corps, Army of the Potomac
May 3 – June 15 Campaign from the Rapidan to the James
May 5-7
Battle of the Wilderness
May 8-21
Spotsylvania Court House
May 10 Nye River
May 12 Assault on Salient
May 21 Ox Ford
May 23-26 North Anna River
May 26-28 On line of the Pamunkey
May 28-31 Totopotomoy
June 1 1st Brigade, First Division, 9th Army Corps
June 1-12
Cold Harbor
June 1-3 Bethesda Church
June 16-18 First Assault on Petersburg
June 16 Siege of Petersburg begins
July Attached to 2nd Brigade, 1st Division, 9th Army Corps
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 Grove Church
October 27-28 Boydton Plank Road, Hatcher’s Run
March 25 Fort Steadman, Petersburg
March 28 Appomattox Campaign
April 2 Assault on and fall of Petersburg
April 3 Occupation of Petersburg
April 3-9 March to Farmville
April 20-24 Moved to Petersburg and City Point
April 26-28 To Alexandria
May 23 Grand Review
May – July Duty in the Dept. of Washington
July 31 Mustered out