Big Round Top is a boulder-strewn hill notable as the topographic high point of the Gettysburg Battlefield and for 1863 American Civil War engagements for which Medals of Honor were awarded. In addition to battle monuments, a historic postbellum structure on the uninhabited hill is the Big Round Top Observation Tower Foundation Ruin. Geography Big Round Top is the southern peak of the Gettysburg Battlefield and is within the area encompassed by a drainage depression (southeast, south), Plum Run (west, north), and the Crawford Avenue/Wright Avenue roadway (north, northeast). In addition to Little Round Top, adjacent battlefield locations are South Cavalry Field/Slyder Field (west), Devil's Den (northwest) and the Valley of Death/Slaughter Pen (north). The hill is the highest point of an Adams County dendritic ridge which Plum Run divides at Big Round Top (the drainage divide continues to the east). In addition to Little Round Top (650 ft.), nearby heights are Warfield Ridge (west), hills of 580 ft (southwest) and 540 ft (northwest), and Houck Ridge (north-northwest); while Carr Hill (876 ft) is the nearest higher hill. Devil's Kitchen is rock formation and small cave on the lower slopes of Big Round Top. History The igneous hill was formed 200 million years ago when the outcrop of the Gettysburg sill intruded through the Triassic Gettysburg plain. Subsequent periglacial frost wedging during the Pleistocene formed the hill's extensive boulders. Early human activity included Indigenous people clearing an area on the slope of Big Round Top and established a burial ground about one mile southwest. prior to the 1736 British purchase of the region. Civil War During the Battle of Gettysburg, Big Round Top's slope, timber, and boulders precluded placement of artillery on the summit. At various times during the 1863 battle, positions on Big Round Top formed the left flank of the Union defense. No fighting or other actions took place on Big Round Top on July 1. Battle of Gettysburg, second day On July 2 when "it was growing dark", Big "Round Top was still in [the] possession of the [Confederate] skirmishers, who were firing upon our men. It was important to hold this hill, as…it commanded…our line. I directed Colonel Fisher to occupy it at once. He immediately detached [3 regiments], who advanced promptly, driving the enemy before them" (Crawford's report). After 10 pm, Chamberlain's 20th Maine Volunteer Infantry Regiment occupied a Big Round Top summit position (the