<P> General Buford recognized the importance of the high ground directly to the south of Gettysburg . He knew that if the Confederates could gain control of the heights , Meade 's army would have a hard time dislodging them . He decided to utilize three ridges west of Gettysburg : Herr Ridge , McPherson Ridge , and Seminary Ridge ( proceeding west to east toward the town ) . These were appropriate terrain for a delaying action by his small division against superior Confederate infantry forces , meant to buy time awaiting the arrival of Union infantrymen who could occupy the strong defensive positions south of town , Cemetery Hill , Cemetery Ridge , and Culp 's Hill . Early that morning , Reynolds , who was commanding the Left Wing of the Army of the Potomac , ordered his corps to march to Buford 's location , with the XI Corps ( Maj. Gen. Oliver O. Howard ) to follow closely behind . </P>
why was it important that the union held on to the high ground in gettysburg
if the Confederates could gain control of the heights , Meade 's army would have a hard time dislodging them