It was the site of an unsuccessful assault by Confederate troops against the Union left flank on July 2, 1863, the second day of the Battle of Gettysburg, during the American Civil War.

Little Round Top was successfully defended by a brigade under Colonel Strong Vincent, who was mortally wounded during the fighting and died five days later.

The 20th Maine Volunteer Infantry Regiment, commanded by Colonel Joshua Lawrence Chamberlain, fought its most famous engagement there, culminating in a dramatic downhill bayonet charge.

It is located in Cumberland Township, approximately two miles (3 km) south of Gettysburg, with a rugged, steep slope rising 150 feet (46 m) above nearby Plum Run to the west and strewn with large boulders.

[5] There is no evidence that the name "Little Round Top" was used by soldiers or civilians during the battle, although Col. Franklin A. Haskell, writing to his brother on July 16, 1863, calls it so.

[7] On the second day of the Battle of Gettysburg, July 2, 1863, at about 4 PM, Confederate Lt. Gen. James Longstreet's First Corps began an attack ordered by General Robert E. Lee that was intended to drive northeast up the Emmitsburg Road in the direction of Cemetery Hill, rolling up the Union left flank.

[9] There were four probable reasons for the deviation in the division's direction: first, regiments from the Union III Corps were unexpectedly in the Devil's Den area and they would threaten Hood's right flank if they were not dealt with; second, fire from the 2nd U.S. Sharpshooters at Slyder's farm drew the attention of lead elements of Brig.

Maj. Gen. George Meade, commander of the Army of the Potomac, had ordered Maj. Gen. Daniel Sickles' III Corps to defend the southern end of Cemetery Ridge, which would have just included Little Round Top.

[18][19] During their retreat, the Confederates were subjected to a volley of rifle fire from Company B of the 20th Maine, commanded by Captain Walter G. Morrill, and a few of the 2nd U.S. Sharpshooters, who had been placed by Chamberlain behind a stone wall 150 yards to the east, hoping to guard against an envelopment.

Rallying the crumbling regiment (the smallest in his brigade, with only 263 men) several times, Vincent was mortally wounded during one Texas charge and was succeeded by Colonel James C. Rice.

Reinforced further by Stephen Weed's brigade of the V Corps, Union forces held the hill throughout the rest of the battle, enduring persistent fire from Confederate sharpshooters stationed around Devil's Den.

[24] Little Round Top was the starting point for a Union counterattack at dusk on July 2, conducted by the 3rd Division of the V Corps (the Pennsylvania Reserves) under Brig.

[25] On July 3, Hazlett's battery (six 10-pounder Parrott rifles, now under the command of Lt. Benjamin F. Rittenhouse)[26] fired into the flank of the Confederate assault known as Pickett's Charge.

[27] While agreeing that the fighting on Little Round Top was extremely fierce and soldiers on both sides fought valiantly, historians disagree as to the impact of this particular engagement on the overall outcome of the Battle of Gettysburg.

An example of this view is from 1900: "If the Confederates had seized [Little Round Top] and dragged some of their artillery up there, as they easily could have done, they would have enfiladed Meade's entire line and made it too unhealthy for him to remain there.

In Lee's report after the Gettysburg Campaign, he stated in part, "General Longstreet was delayed by a force occupying the high, rocky hills on the enemy's extreme left, from which his troops could be attacked in reverse as they advanced", suggesting Longstreet was ordered on a course intended to bypass Little Round Top—had the hill been a key objective of the assault, Lee would not have used the phrase "delayed by" in describing the effects of the engagement.

Examining the number of troops available in the vicinity in the late afternoon, he determined that at most 2,650 Confederates could have been available to defend the hill after capturing it, and that these men would have been exhausted from combat and short on ammunition.

In addition, the value of Little Round Top as an artillery position has been overstated—the shape of the crest of the hill forces guns to be placed one behind the other, limiting their effectiveness when engaging targets directly to the north, such as the Union line on Cemetery Ridge.

[32] While Chamberlain and the 20th Maine have gained popularity in the American national consciousness, other historical figures such as Strong Vincent, Patrick O'Rourke, and Charles Hazlett arguably played equal roles in the Union success at Little Round Top.

[citation needed] During visits by 13 generals in 1865, points were identified on Little Round Top at which markers were subsequently erected,[33] and a 40 ft (12 m) observatory was built by 1886,[34] before a stone monument with observation deck was dedicated to the 44th New York in 1892.

Filmmaker Ken Burns praised Chamberlain in his PBS documentary The Civil War and in subsequent interviews for possibly saving the Union with his actions during the engagement.