Battle of the Iron Triangle Battle of the Iron Triangle The Battle of the Iron Triangle took place from 16 May to 20 November 1974, when the People's Army of Vietnam (PAVN) 9th Division captured Rach Bap and An Dien The Army of the Republic of Vietnam (ARVN) regained the lost towns in a series of costly counterattacks. The Iron Triangle was an important strategic location, bounded on the north by the jungle and overgrown rubber plantations of the Long Nguyen Secret Zone, on the west by the Saigon River and on the east by the smaller but unfordable obstacle of the Thi Thinh River.
Battle of the Iron Triangle sent the 141st Regiment, 7th Division south from its position along Highway 13, north of Lai Khê, to reinforce the 9th Division north of Base 82. The 9th Division meanwhile began shifting the 272nd Regiment north from the southern part of the Iron Triangle to assist in the defense of Base 82 and Rach Bap. The summer monsoon had arrived in Bình Dương Province and rains and low cloud cover further reduced the effectiveness of RVNAF support for the attack. A dense rubber plantation northwest of Base 82 provided excellent concealment for supporting defensive positions and observation of local Route