The Vietnam War (Vietnamese: Chiến tranh Việt Nam), also known as the Second Indochina War, and in Vietnam as the Resistance War Against America (Vietnamese: Kháng chiến chống Mỹ) or simply the American War, was a conflict in Vietnam, Laos, and Cambodia from 1 November 1955 to the fall of Saigon on 30 April 1975.

The End of Pol Pot . During the entire war, Cambodia was used as a supply depot (caches), and sanctuary for NVA. A map of modern day Laos, showing its location west of Vietnam. In Ohio, at Kent State University, students set fire to the Reserve Officer Training Corps (ROTC) building. While Ho Chi Minh City during the Vietnam trip boasts impressive French colonial architecture and the Vietnamese War Museum, Siem Reap in Cambodia is home to the famous Angkor Wat temple complex.
President Lyndon B. Johnson had rejected this strategy as he feared it would undermine the anti-communist government of Prince Sihanouk. --Army "Stunning in its research and highly sophisticated in its analysis, this is far and away the best study we have of the tactics and strategy used during the invasion of Cambodia." The war began on March 11, 1967, and ended on April 17, 1975.

Cambodia on April 30, 1970, that brought Cambodia into the Vietnam war.
Many Americans opposed the Vietnam War. The fall of Cambodia and Laos, coupled with the fall of South Vietnam, marked the bitter end to the Vietnam War and the struggle to contain communism in Southeast Asia.

The fall of Cambodia and Laos, coupled with the fall of South Vietnam, marked the bitter end to the Vietnam War and the struggle to contain communism in Southeast Asia.

--Robert K. Brigham, author of Guerrilla Diplomacy: The NLF's Foreign Relations and the Vietnam War When media outlets publicized the events in Cambodia, critics of the war became more vocal. Since 1973, the remains of more than 1,000 Americans killed in the Vietnam War have been identified and returned to their families for burial with full military honors. Cambodia was an unpopular war for Vietnam, said Carlyle Thayer, an expert on Vietnam and emeritus professor at the University of New South Wales at the Australian Defence Force Academy in Canberra. Beginning with low-level cross-border raids and escalating …

It was me Vietnamese communists who spread the Vietnam war inside Cambodia. The Vietnam War was a long, costly and divisive conflict that pitted the communist government of North Vietnam against South Vietnam and its principal ally, the United States.