Rung Sat Special Zone (Vietnamese: Đặc khu Rừng Sác) was the name given during the Vietnam War by the South Vietnam Government and American forces to a large area of the Sác Forest (Vietnamese Rừng Sác), which is today known as the Cần Giờ Mangrove Forest. It was also known as the "Forest of Assassins." The name was derived from a misinterpretation of the Vietnamese word Sát to mean "assassin". The actual name, Rừng Sác, is a Sino-Vietnamese word that roughly translated to "salty forest," a reference to its proximity to the saltwater marshes of the delta.
The Sác Forest comprises approximately 1,256 square kilometres (485 sq mi) of tidal mangrove swamp including over 4,800 kilometres (3,000 mi) of interlocking streams located approximately 36 kilometres (22 mi) south-southeast of Saigon. Its boundaries in 1962 were Nhà Bè District and Nhơn Trạch District to the north, Long An Province and Tiền Giang Province to the west, Phước Tuy Province to the east and the South China Sea to the south.
On 8 June 1962, the South Vietnamese Government organized the Rung Sat Special Zone (Đặc khu Rừng Sác) as a military region in order to defend the Lòng Tàu River, the main shipping channel from Saigon to Vũng Tàu.
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.
Following attacks on allied shipping on the Lòng Tàu River, from 27 March to 6 April 1966, 1st Battalion 5th Marines and two 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. 
Following the conclusion of Operation Jackstay, the Marines handed over responsibility for the zone to the 1st Battalion, 18th Infantry Regiment. Responsibility for security in the zone was then passed to the Mobile Riverine Force and the 9th Infantry Division.
- Tucker, Spencer C. (2011). The Encyclopedia of the Vietnam War. p. 407. "The Saigon River, which meandered through the Rung Sat Special Zone, a VC-dominated area also known as the “Forest of Assassins,” provided allied seaborne logistics a direct route to the South Vietnamese capital."
- Haines, E. R. (2013). "Rung Sat Special Zone Intelligence Study". Mobile Riverine Force Association. Retrieved 28 May 2013.
- Kelley, p 5-450
- "Operations List". Vietnam Center and Archive. 2011. Retrieved 28 May 2013.
- http://www.flyarmy.org/panel/battle/66032600.HTM[dead link]
- Pezzoli, Ray (December 2001). "Vanguards in the Rung Sat". historynet.com. Retrieved 28 May 2013.
- Kelley, Michael P. (2002). Where We Were in Vietnam. Hellgate Press, Central Point, Oregon. ISBN 978-1-55571-625-7.
- Navy map of the Rung Sat Special Zone
- The short film STAFF FILM REPORT 66-19A (1966) is available for free download at the Internet Archive [more]
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