The 20th Maine Infantry Regiment lost 9 officers and 138 enlisted men killed or mortally wounded and 1 officer and 145 enlisted men to disease during the Civil War.

It is honored by three monuments at Gettysburg.

August 29 Organized at Portland and mustered in under Colonel Adelbert Ames and Lieutenant Colonel Joshua L. Chamberlain
September 3 Left State for Alexandria, Va. Attached to 1st Brigade, 1st Division, 5th Army Corps, Army of the Potomac
September 16-17
Battle of Antietam

The regiment was not engaged in the battle, staying in reserve with much of the Fifth Corps

September 19
Battle of Shephardstown

Corporal Waterhouse became the regiment’s first casualty when he was wounded in the foot. Two other men were wounded, and Lieutenant Colonel Chamberlain lost the first of many horses shot from under him during the Civil War.

October Attached to 3rd Brigade, 1st Division, 5th Army Corps
October –
Advance to Falmouth, Va.
December 6 Two men froze to death in their tent as four inches of snow fell
December 12-15
Battle of Fredericksburg

The regiment lost four men killed and 32 wounded, charging deadly Marye’s Heights late in the day on the 13th and spending the next day and two nights lying in the open in front of Confederate positions. Serving as a rear guard, the 20th Maine was one of the last regiments back across the Rapahnnock.

December 20-30 Expedition to Richards and Ellis Fords
January 20-24 “Mud March”
April 17 Surgeon N. P. Monroe reported 84 cases of smallpox in the regiment. Three men died of the disease, which was probably due to a botched innoculation.
April 19 The regiment was moved to Quarantine Hill, while Colonel Ames was transferred to General Meade’s staff at Corps Headquarters
April 27 Chancellorsville Campaign
May 1-5
Battle of Chancellorsville

The regiment missed the battle due to being under quarantine. Lieutenant Colonel Chamberlain pleaded with Brigadier General Daniel Butterfield to put the men into the fight and was refused. Chamberlain replied, “If we couldn’t do anything else we would give the Rebels the smallpox!” Instead, the regiment was assigned to guard duty on the telegraph line from headquarters to United States Ford, although Lt. Colonel Chamberlain joined the First Division for the fight and loses another horse shot from underneath him.

May 6 The regiment returned to camp in the night in a driving rainstorm as the army retreated back across the Rappahannock.
May 20 Colonel Ames was promoted to brigadier general and given command of a brigade in the 11th Corps, and Lt. Colonel Chamberlain was promoted to colonel and took command of the Regiment. The regiment was reduced to around 400 men.
May 23 About 120 three-year men from the 2nd Maine Infantry Regiment were transferred to the 20th at the end of the 2nd’s two-year service.
June 12 Gettysburg Campaign
June 17 Aldie
June 21 Upperville
June 24 Middleburg
July 1-3
Battle of Gettysburg

From the main monument on Little Round Top:

Here the 20th Maine Regiment Col. J. L. Chamberlain commanding, forming the extreme left of the national line of battle on the 2nd day of July 1863, repulsed the attack of the extreme right of Longstreet’s Corps and charged in turn, capturing 308 prisoners. The regiment lost 38 killed or mortally wounded and 93 wounded out of 358 engaged.

Names of the officers and men of the Twentieth Maine Volunteers who were killed or died of wounds received in this action: Co. C, Capt. Charles W. Billings;  Co. I, 1 Lieut. Arad H. Linscott; Co. G, 2nd Lieut. Warren L. Kendall; Co. A, Corp. Joseph D.Simpson, Priv. John Reed Jr., 1st Serg. Issac W. Estes, Priv. Elliott L. Fogg, Priv. Moses Davis,  Priv. Oliver L. Stevens,  Priv. Charles M. Beadle, Corp. Willard Pinkham,  Corp. Andrew D. Maybury, Priv. Stephen A. Prescott, Corp. Paschal M. Tripp,  Corp. John Foss, Corp. William S. Hodgdon, Priv. Seth W. Clark, Priv. John Wentworth;  Co. F, Priv. Oscar Wyer, Priv.  Charles F. Hall, Priv.  Benjamin W. Grant, Priv. Frank B. Curtis, Priv. Elfin J. Ross, Co. G, Serg. William S. Jordan, Corp. Melville C. Law, Priv. James A. Knight; Co. H, 1st Serg. Charles W. Steele, Serg.George W. Buck, Serg  Isaac M. Lathrop, Priv. Aaaron Adams, Priv. Goodwin S. Ireland, Priv.  Iredell Lamson; Co. I, Priv. Alexander E. Lester; Co. K, 1st Serg. George S. Noyes, Priv. James R. Merrill, Priv.  William F. Merrill, Priv.  Stephen C. Chase, Priv. Williard W. Buxton

From the Company B monument, located about 50 yards to the east of the main monument on Little Round Top:

Position of Company B, 20th Me. Vols., Capt. Walter G. Morrill, detached as skirmishers, attacking the enemy’s right flank, afternoon of July 2, 1863.

From the regiment’s monument near the summit of Big Round Top:

The 20th Maine Reg. 3d Brig. 1st. Div. 5th Corps Colonel Joshua L. Chamberlain captured and held this position on the evening of July 2d, 1863, pursuing the enemy from its front on the line marked by its monument below. The Regt. lost in the battle 130 killed and wounded out of 358 engaged. This monument marks the extreme left of the Union line during the battle of the 3d day.

July 5-24 Pursuit of Lee to Manassas Gap, Va.
August 29 Colonel Chamberlain took command of the brigade. Captain Ellis Spear was promoted to major and took command of the Regiment.
October 9-22 Bristoe Campaign
November 7-8 Advance to line of the Rappahannock
November 7 Rappahannock Station
November Colonel Chamberlain returned to Maine on an extended sick leave for ‘malarial fever.’
November 26-
December 2
Mine Run Campaign
April Colonel Chamberlain returned from sick leave and court martial duty in Washington to resume command of the Regiment.
May Campaign from the Rapidan to the James
May 5-7
Battle of the Wilderness
May 8 Laurel Hill
May 8-21
Battle of Spotsylvania Court House
May 23-26 North Anna River
May 23 Jericho Mills
May 26-28 Line of the Pamunkey
May 28-31 Totopotomoy
June 1-3
Battle of Cold Harbor
June 1-3 Bethesda Church
June Colonel Chamberlain took over brigade command and Major Ellis Spear took command of the Regiment.
June 16-19
First Assault on Petersburg
June 18 Siege of Petersburg begins
June 18
Rive’s Salient

Colonel Chamberlain was badly wounded in the right hip and groin. It was considered a mortal wound and was reported as such in the newspapers, and General Grant promoted him to brigadier general based on the recommendation of Major General Gouverneur K. Warren. But Chamberlain recovered and returned to the army by the end of the year, serving until the end of the war. It is believed the wound was eventually responsible for Chamberlain’s death, 50 years later in 1914.

June 21-23
Weldon Railroad
July 30 Mine Explosion, Petersburg (Reserve)
August 18-21 Six Mile House, Weldon Railroad
September 29 –
October 2
Poplar Springs Church, Peeble’s Farm
September Major Spear brevetted lieutenant colonel of volunteers for “gallant and distinguished serves” at Peeble’s Farm
October 27-28
Boydton Plank Road (First Hatcher’s Run)
December 7-11 Warren’s Hicksford Raid
February 5-7
Dabney’s Mills, Hatcher’s Run
March 28 Appomattox Campaign
March 29 White Oak Road. Brevet Lieutenant Colonel Spear was brevetted colonel for “faithful and meritorious service”
March 30 Quaker Road
March 30-31 Boydton Road
April 1
Battle of Five Forks
April 5 Amelia C. H.
April 6 High Bridge
April 9 Appomattox Court House
Surrender of Lee and his army
May 2-12 March to Washington, D.C.
May 23 Grand Review
May 29 Brevet Colonel Spear was promoted to full colonel
June 4 Old members mustered out
July 16 Regiment mustered out under Colonel Spear