No one used to say, "Republic of South Vietnam", or "I'm going to South Vietnam", it was usually said as, "I'm going to Vietnam", hence the word Vietnam...when in reality we w…ere headed for SOUTH Vietnam, Vietnam was two separate countries. North and South Vietnam were simply countries in the south eastern portion of Asia (on the continent of Eurasia)..
You certainly weren't going to NORTH Vietnam. Not unless you were either an aircrewman or pilot. Those men actually fought in the skies of NORTH Vietnam. Aerial dog-fights (air combat) over South Vietnam rarely if ever happened. Nearly, if not all, of our POWs were airmen shot down over NORTH Vietnam. ( Full Answer )