Rung Sat Special Zone, also known as the "Forest of Assassins" was an area of approximately 1256 square km of tidal mangrove swamp including over 4800 km of interlocking streams located approximately 36 km south-southeast of Saigon. Its boundaries were Nhà Bè District and Nhơn Trạch District to the north, Long An Province and Go Cong Province to the west, Phước Tuy Province to the east and the South China Sea to the south[1].[2]
On 8 June 1962, the South Vietnamese Government organized the Rung Sat Special Zone (Dac Khu Rung Sat) as a military region in order to defend the Lòng Tàu River, the main shipping channel from Saigon to Vũng Tàu[3].
The Vietcong established base areas in the zone from the late 1950s and in April 1966 COSVN designated the area as the D-10 Special Military Zone[4].
Due to the difficult conditions for ground operations within the zone, the VC regarded it as a safe area, however from 1965 onwards the USAF began defoliating the area as part of Operation Ranch Hand[5].
Following attacks on allied shipping on the Lòng Tàu River, from 27 March to 6 April 1966, 1st Battalion, 5th Marines and 2 Battalions of Vietnamese Marines launched Operation Jackstay, a search and clear operation along the Lòng Tàu shipping channel killing 63 VC and seizing and destroying large supply caches[6][7].
Following the conclusion of Operation Jackstay, the Marines handed over responsibility for the zone to the 1st Battalion, 18th Infantry Regiment[8]. Responsibility for security in the zone was then passed to the Mobile Riverine Force and the 9th Infantry Division.
