As part of Operation Prairie, the 3d Battalion, 4th Marines attacked North Vietnamese Army installations along Razorback Ridge in the Quang Tri province on September 22. It was the hardest fighting of the seven-week-old campaign. Helicopters assisted ground forces throughout the fighting, now and then bombing the jungle to clear the way for the Marines’ advance and resupplying the men each night to leave them free of extra gear as they searched the hills for the North Vietnamese Army. By early October North Vietnamese Army Division 324B had abandoned the fight and slipped back across the demilitarized zone into North Vietnam.