On the second day of the Battle of Gettysburg, July 2, 1863, Warren initiated the defense of Little Round Top, recognizing the importance of the undefended position on the left flank of the Union Army, and directing, on his own initiative, the brigade of Col. Strong Vincent to occupy it just minutes before it was attacked.
På 2. dagen af Slaget ved Gettysburg, 2. juli 1863, iværksatte Warren forsvaret af Little Round Top idet han indså vigtigheden af den ubesatte position på Unionshærens venstre flanke og placerede på eget initiativ oberst Strong Vincents brigade derpå, blot minutter inden den blev angrebet.