When did the Vietnam war ended?

Answer 1

The 1973 Paris Accord required all external troops to be withdrawn and all external supply of war materials to cease. The Free World side honoured this. North Vietnam and its backers USSR and China did not. The Ho Chi Minh Trail was expanded to a four lane highway with a petroleum pipeline beside it to pour supply into South Vietnam.

In 1975 the North Vietnam regular army attacked across the border from Laos with conventional arms including tanks and artillery, supported by this supply line. The South Vietnam forces, without resupply, had to conserve ammunition, and could put up little credible resistance to this overwhelming force. The South Vietnamese were decisively defeated in the field and capitulated to avoid unneccessary bloodshed.

Acting President of South Vietnam Duong Van Minh surrendered on 30 April 1975.

Answer 2

When the North Vietnamese Army Tanks crashed through the palace gates of South Vietnam and parked them on the front lawn on 30 April 1975; the war was over.

Answer 3

30 April 1975.