 The hill's relative location to Route 9 gave the Rockpile an added significance.Route 9 is a road that runs parallel to the DMZ from Dong Ha, past the Rockpile, and on through Khe Sanh before becoming a dirt track that crosses the border into Laos.In addition, its location gave the American forces an upper hand in the defense and supply of Khe Sanh Combat Base, Ca Lu Combat Base, and Camp Carroll as it was possible to interdict potential ambushes along Route 9.