Côn Sơn Island

Notable prisoners held at Côn Sơn in the 1930s included Phạm Văn Đồng, Nguyễn An Ninh and Lê Đức Thọ.

The facilities were reopened with improved conditions some years later however, to temporarily incarcerate boat people captured by local coast guards until the late 1980s.

[citation needed] At the request of Secretary of Defense Robert McNamara, the U.S. Coast Guard started pre-construction plans for a chain of Loran-C radio stations to serve Southeast Asia 15 January 1966 in support of Operation Tight Reign during the Vietnam War.

It consisted of a 625 foot (191 m) tower, transmitter equipment buildings, fuel tanks, generators and barracks for personnel located on the north end of Con Son Island.

Station Con Son stayed on the air until 1246 local time on 29 April 1975, after which the crew over-sped the generators and damaged critical pieces of electronic gear.