TO 1/3 COMBAT HISTORY FILE AND THE BOOK, "SEMPER FI VIETNAM"
On 1 June, Operation Cimarron began in the same area and with the same formations. The operation lasted through 2 July, producing only light contact. The Marines discovered and destroyed several large, abandoned, fortified positions in the area southwest of Con Thien and unit sweeps located numerous enemy graves and several supply caches.
While Cimarron progressed, the land clearing project from Con Thien through Gio Linh to the high water mark on the coast reached completion by 1 July. The Marine engineers widened the previously cleared area to 600 meters for the entire 13.5 kilometers of its length. The 11th Engineer Battalion contributed more than 10,000 man hours and 4,500 tractor hours to this hazardous effort.
During the last days of Cimarron a sharp increase in enemy artillery activity, coupled with several small but intense engagements between patrols and dug in NVA units around Con Thien, indicated that the enemy was preparing for renewed offensive operations in the area. There was to be much hole digging and sandbag filling before the summer ended.