The ceasefire had been in effect for nine months when the artillery began falling on Bu Prang. The Paris Peace Accords, signed on 27 January 1973, had formally ended direct American military involvement and established a notional stop-fire. But in Quang Duc Province — a highland salient where Vietnam's Central Highlands push down toward the Cambodian border — neither side had stopped preparing. Through the spring and summer of 1973, North Vietnamese engineers and infantry were quietly extending a supply route south from Cambodia, and the South Vietnamese were watching. By October, the watching was over. The Battle of Quang Duc, fought from 30 October to 10 December 1973, was one of the most significant post-ceasefire engagements of the war — a reminder that ceasefires, like roads, mean little when both sides still have reasons to fight.
Quang Duc Province occupied a peculiar strategic position. Its timber made it commercially valuable; its roads made it militarily essential. Highway 14 threading through the province was the last overland link connecting Ban Me Thuot to the north with Phước Long to the south after the PAVN had cut the direct route through Bình Dương Province. For the North Vietnamese, the same highway represented an opportunity: extending their supply network — Route 14 — out of Cambodia's Mondulkiri Province and into South Vietnam required threading it through the Quang Duc border region near Bu Prang. Both sides understood that whoever controlled the road junctions at Bu Prang, Dak Song, and Kien Duc controlled the province. The garrison defending them was thin: three Regional Force battalions supported by twelve 105-mm howitzers, most of the soldiers Montagnard tribespeople whose ancestors had lived in these highlands for generations.
What Colonel Nguyen Hau Thien, Quang Duc's province chief, faced in the autumn of 1973 was not the light harassment he had been managing since May. COSVN had assembled a force designated Unit 95 — effectively a division in strength — at Bù Đốp camp to the east. It included the 205th and 271st Infantry Regiments, the 429th Sapper Regiment, a tank battalion, the 208th Artillery Regiment with 85-mm and 122-mm guns and 120-mm mortars, antiaircraft artillery, and SA-7 surface-to-air missiles. South Vietnamese II Corps headquarters did not yet grasp the scale of what was coming. Thien had asked for reinforcements and received a single battalion — which he then complained was inadequate. He was right. By the time the PAVN's 208th Artillery began a five-day fire rehearsal on 23 October, the trap was effectively set.
The assault on Bu Prang and Bu Bong began just before first light on 4 November 1973. The 205th Regiment, with sapper units and two companies of tanks and armored personnel carriers, hit the defensive positions. The outnumbered garrison — an RF company, an engineer platoon, and two artillery platoons — had no realistic chance of holding against a combined-arms assault of this size. Two howitzers were destroyed in place; the other two were towed away by the PAVN. The four RF battalions positioned outside the perimeter were dispersed into the forested hills. During the assault on Bu Bong, the PAVN 205th Regiment's commander was seriously wounded and evacuated. The camps fell in a single morning. The province capital of Gia Nghĩa, its last road connection cut when Dak Song fell shortly after, was suddenly isolated.
II Corps commander General Nguyễn Văn Toàn responded faster than the PAVN expected. He ordered the ARVN 23rd Division to pull the 53rd Infantry from Kontum and push it south toward Ban Me Thuot, then fly elements directly into Nhon Co airfield near Gia Nghĩa even as the airstrip was taking artillery and rocket fire. Within days, the 1st Battalion of the 53rd was approaching Dak Song from the north, while the 2nd Battalion moved north from Nhon Co along Highway 14 toward the captured camps. On 14 November, the 2nd Battalion stopped a PAVN tank-infantry assault cold, destroying two tanks and forcing the PAVN 3rd Battalion, 205th Regiment, to withdraw — barely 100 effective soldiers remaining. The 21st Ranger Group and two more regiments of the 23rd Division arrived as the fighting intensified around Kien Duc. By early December, the first convoy in three months had reached Gia Nghĩa from Ban Me Thuot.
The final battle came at the Kien Duc road junction on 4 December. After artillery and air preparation, the 45th Infantry attacked the PAVN positions. The 205th Regiment's 1st Battalion lost 40 percent of its strength; the sapper company attached to it was so depleted it was disbanded. A later rallier reported the 205th suffered more than 200 killed and 400 wounded in the entire campaign. South Vietnamese losses in the 53rd Regiment alone included 40 killed, 40 wounded, and 80 missing before the junction was retaken. By Christmas, Highway 14 was secured again. The PAVN had failed to establish its supply corridor. South Vietnam had paid a serious price to deny it. Eighteen months later, the same province and the same roads would feature in the collapse that ended the war — but in December 1973, at least, the highland defenders had held.
The Battle of Quang Duc was fought across a roughly 50-kilometer arc of Central Highlands terrain centered near 12.245°N, 107.436°E in what is now Đắk Nông province, Vietnam. Key sites — Bu Prang, Bu Bong, Dak Song, and the Kien Duc road junction — are spread along Highway 14 south from the Cambodian border. From the air at 8,000–12,000 feet, the terrain shows as rolling forested highlands cut by road corridors; the border with Cambodia's Mondulkiri Province is visible to the northwest. The nearest airport with regular service is Buôn Ma Thuột Airport (BMV), approximately 80 km to the north. Nhon Co airfield, which ARVN C-130s used during the battle under fire, is near Gia Nghĩa at the center of the former province.