Nguyễn Hợp Đoàn (28 August 1928 – 15 April 2002) was to be the last Mayor of Saigon, the capital of South Vietnam and Governor of Gia Dinh Province, before the fall of Saigon that led to the reunification of Vietnam under the Communist party in 1975.

He served as Commanding Officer of 705th Battalion, Commanding Officer of 42nd Regiment (Thai Binh), Commanding Officer of 14th Infantry Regiment of the 9th Infantry Division, Deputy Director National School of Psychological Warfare, Deputy Chief of Staff for 4th Corp Psychological Warfare and Chief of Staff of 9th Division.

He also served as High Command’s Chief of Staff of Vietnam's Airborne Rangers (81st Airborne Commando Battalion) in 1961 and High Command’s Chief of Staff of Vietnam's Special Forces in 1965.

Dalat was also a center of learning, with many boarding schools, universities, military academies and seminaries.

South Vietnam's sole nuclear reactor and associated scientists and personnel were based in Da Lat.