The approaching Confederates were the Alabama Brigade of Hood's Division, commanded by Brig. Gen. Evander M. Law. Dispatching the 4th, 15th, and 47th Alabama, and the 4th and 5th Texas to Little Round Top, Law ordered his men to take the hill. The men were exhausted, having marched more than 20 miles (32 km) that day to reach this point. The day was hot and their canteens were empty. Approaching the Union line on the crest of the hill, Law's men were thrown back by the first Union volley and withdrew briefly to regroup. The 15th Alabama, commanded by Col. William C. Oates, repositioned further right and attempted to find the Union left flank.^[82]

The Unioin left flank consisted of the 386 officers and men of the 20th Maine regiment and the 83rd Pennsylvania. Seeing the Confederates shifting around his flank, Chamberlain first stretched his line to the point where his men were in a single-file line, then ordered the southernmost half of his line to swing back during a lull following another Confederate charge. It was there that they "refused the line"—formed an angle to the main line in an attempt to prevent the Confederate flanking maneuver. Despite heavy losses, the 20th Maine held through two subsequent charges by the 15th Alabama and other Confederate regiments for a total of ninety minutes.^[83]