The Battle of Suoi Bong Trang (23–24 February 1966) was an engagement fought between US, Australian and New Zealand forces, and the Viet Cong and North Vietnamese Army during the Vietnam War.

During the fighting, soldiers from the US 1st Brigade, 1st Infantry Division and the 1st Battalion, Royal Australian Regiment (1 RAR), which had been attached for the operation, fought off a regimental-sized Viet Cong night assault.

[1][2] In response to the American moves, Viet Cong Local Force elements began harassing the sappers, subjecting them daily to sniping, laying mines and carrying out sabotage in an effort to hamper construction.

[5] The US 1st Brigade under the command of Colonel Edgar N. Glotzbach was allocated the task, and he assigned one of his three battalions to guard the engineers on a rotating basis, while the other two would probe the Viet Cong positions nearby in order to keep them off balance.

[8] Headquarters US 1st Brigade was located about 1,000 metres (1,100 yd) east of the engineer base camp in the vicinity of the hamlet of Tan Binh, just north of the new roadway and less than 5 kilometres (3.1 mi) west of Route 16.

Preece immediately warned Glotzbach of an imminent attack, and then informed Sargent that the Australians were moving to set up a defensive position, recommending that the engineers relocate in order to join them.

[2][8][11] By 20:00 they had completed a 25-kilometre (16 mi) approach march and were in assembly areas near the village of Ap Bo, using local women and youths as porters to carry ammunition, equipment and supplies.

Meanwhile, a small Australian standing patrol that had deployed forward of the company main defensive position under the command of Private Walter Brunalli, observed the lights moving closer, east of the US 1st Brigade's headquarters.

The forward American listening posts had detected small groups of Viet Cong moving outside the perimeter, killing two and forcing the remainder to withdraw into the darkness after one of the sentries opened fire.

[17] Earlier, a number of Australian ambushes had intercepted Viet Cong pathfinder groups and this had largely prevented the communists from conducting a final reconnaissance of their objectives.

Unaware of the newly strengthened defences, they had assaulted into the combined firepower of two American field artillery batteries firing over open sights, as well as tanks supported by infantry.

Using anti-personnel canister, flechette and splintex rounds, as well as prepositioned banks of Claymore mines, the Americans broke up several assaults with heavy casualties, while the Australians poured small arms fire into the flank of what was now turning into a costly and futile attack.

Moving to achieve a clean break, the patrol engaged another group of 10 Viet Cong with a volley of small arms fire, before withdrawing 30 metres (33 yd) towards the company position in the darkness.

[16] With the Viet Cong line of withdrawal carrying them past the Australian position, heavy fire was maintained on them as they attempted a partial retreat, resulting in further casualties.

[20] Others had been disintegrated by artillery and tank fire and the battlefield was littered with shattered human remains, including severed limbs and chunks of flesh, while red pulp covered the rubber trees that were still standing.

[2] The villagers of Ap Bo were again used by the Viet Cong to carry many of the dead and wounded from the battlefield with ox carts, and they also suffered a number of casualties from artillery and mortar fire landing in the area.

[22] Meanwhile, following the attack at Tan Binh the Viet Cong attempted to avoid further contact, choosing instead to harass the American work parties with occasional mortar and sniper fire.

The Americans then launched an extensive civic action program in an attempt to consolidate their gains, repairing damaged houses, distributing food and providing basic health care to the local population.

Despite such efforts though, American commanders were pessimistic about the possibility of achieving any long term gains in Binh Duong Province unless the South Vietnamese Army was able to provide lasting protection for the local population.