The Division played a supporting role in the Battle of Khe Sanh, largely tasked with keeping Route 9 from Ca Lu to the Khe Sanh Combat Base closed. On 24 January 1968 elements of the 320th ambushed a Marine convoy between Dong Ha and Camp Carroll and then ambushed the relief force from the 2nd Battalion 9th Marines killing nine Marines. The subsequent Marine clearing operation, including the "Battle of Mike's Hill", lasted until 29 January and resulted in 21 Marines killed and 130 PAVN killed and six captured.