 Mountains positioned on either side of Route 9 near the Rockpile provided the NVA and VC with excellent cover to mount any ambushes against allied convoys travelling through the area.For these reasons the United States high command decided to keep the Rockpile and the surrounding area as secure as possible for several years during the height of the conflict.Ultimately, the United States' occupation of the Rockpile forced the NVA and VC to use higher and more dangerous infiltration routes to the west closer to Laos because the normal routes through the Cam Lo and Dong Ha area were essentially closed off.