There are two monuments and a company position marker to the 20th Maine at Gettysburg.

The main monument is on the southeast side of Little Round Top. (39.789476° N , 77.236146° W; Google map; Monument map: Little Round Top) This marks the center of the line the regiment held during its famous defense of Little Round Top on July 2nd. It was dedicated in 1886 by the State of Maine.

A marker showing the position of the regiment’s Company B during the defense of Little Round Top is 100 yards to the east of the main monument. (39.788895° N, 77.234721° N; Google map) Captain Morrill and about 40 men of company B joined by a group of United States Sharpshooters were placed here to provide some protection to the flank of the 20th Maine.

A monument near the summit of Big Round Top shows the position to which the 20th Maine advanced during the evening July 2nd and which it held through the morning of the 3rd. (39.786642° N, 77.239544° W; Google map; Monument map: Big Round Top) It was dedicated in 1889.

Colonel Joshua Lawrence Chamberlain, the 20th Maine’s commander at the Battle of Gettysburg, has become one the most famous men of the Civil War thanks to the novel The Killer Angels and the movie Gettysburg. He was wounded six times, earned the Medal of Honor, and went on after the war to serve as Governor of Maine and President of Bowdoin College.

The 20th Maine brought 386 men to the field, of whom 29 were killed, 91 wounded, and 5 missing. The names of the casualties are listed on the monument on Little Round Top (see below).

The Medal of honor as it looked at the time of the Civil War

Colonel Chamberlain and Sergeant Andrew Tozier were awarded the Medal of Honor for their actions on July 2nd. Chamberlain for “daring heroism and great tenacity in holding his position on the Little Round Top against repeated assaults, and carrying the advance position on the Great Round Top” Tozier who, “At the crisis of the engagement this soldier, a color bearer, stood alone in an advanced position, the regiment having been borne back, and defended his colors with musket and ammunition picked up at his feet.”

Official Records thumbnail
See Colonel Chamberlain’s Official Report for the 20th Maine Regiment in the Battle of Gettysburg and of Captain Clark’s report for the end of the campaign.
5th Corps Headquarters Flag Flag for the First Division, Fifth Corps
Attached to the 3rd Brigade, 1st DivisionFifth Corps, Army of the Potomac

Monument to the 20th Maine Infantry on Little Round Top at Gettysburg

From the front of the monument on Little Round Top:

Twentieth Maine
Volunteer Infantry
Third Brig. First Div.
Fifth Corps

From the right side of 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.

This monument erected by survivors of this regiment A.D. 1888. Marks very nearly the spot where the colors stood.

From the left side of the main monument:

Names of the officers and men of the Twentieth Maine Volunteers who were killed or died of wounds received in this action:

Capt. Charles W. Billings Co. C
1 Lieut. Arad H. Linscott ”  I
2nd Lieut. Warren L. Kendall ” G
Corp. Joseph D.Simpson ” A
Priv. John Reed Jr. ” A
1st Serg. Issac W. Estes ” C
Priv. Elliott L. Fogg ” C
”  Moses Davis ” C
”  Oliver L. Stevens ” C
”  Charles M. Beadle ” C
Corp. Willard Pinkham ” D
”  Andrew D. Maybury ” D
Priv. Stephen A. Prescott ” D
Corp. Paschal M. Tripp ” F
”  John Foss ” F
”  William S. Hodgdon ” F
Priv. Seth W. Clark ” F
”  John Wentworth
  ” F

From the rear of the main monument:

Priv. Oscar Wyer Co. F
”  Charles F. Hall ” F
”  Benjamin W. Grant ” F
”  Frank B. Curtis ” F
”  Elfin J. Ross ” F
Serg. William S. Jordan ” G
Corp. Melville C. Law ” G
Priv. James A. Knight ” G
1st Serg. Charles W. Steele ” H
Serg.George W. Buck ” H
”  Isaac M. Lathrop ” H
Priv. Aaaron Adams ” H
”  Goodwin S. Ireland ” H
”   Iredell Lamson ” H
”  Alexander E. Lester ”  I
1st Serg. George S. Noyes ” K
Priv. James R. Merrill ” K
”  William F. Merrill ” K
”  Stephen C. Chase ” K
”  Williard W. Buxton ” K

Monument to Company B of the 20th Maine Infantry at Gettysburg

Monument to Company B of the 20th Maine Infantry at Gettysburg

From the monument to Company B 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.

Monument to the 20th Maine Infantry on Big Round Top at Gettysburg

Monument to the 20th Maine Infantry on Big Round Top at Gettysburg

From the monument on 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.

 See more about the 20th Maine in the Civil War