It's called Mekong River.
Ground fighting occurred through out the Republic of South Vietnam. Unofficially, fighting occurred in Lao's and Cambodia along the South Vietnamese borders. Air Strikes occurred in North Vietnam, South Vietnam, Cambodia, and Laos.
Laos & Cambodia
Cambodia is south of Laos and west of Vietnam.
North and South Vietnam, Laos and Cambodia
Notably Laos and Cambodia
Laos and Cambodia
South Vietnam, North Vietnam, Laos, and Cambodia.
China,Thailand, Laos, Cambodia and South Vietnam
The invasion of Cambodia in June 1970 by the United States led to the destruction of the Ho Chi Minh Trail and the dislocation of the Viet Cong. The Ho Chi Minh Trail was a path that went from North Vietnam to South Vietnam through Cambodia and Laos. The North Vietnamese used it to send supplies to The Viet Cong in South Vietnam.
Cambodia was officially neutral during the war.
The Ho Chi Minh trail went through the bordering countries of Laos and Cambodia to get into South Vietnam's southern regions in relative safety.
There are large tracts of forest in Cambodia, despite the deforestation campaigns waged on Cambodia during the American(vietnam)war. During the Vietnam War, there were many forests in Cambodia, Laos and South Vietnam. Only Airmen can report on forests for North Vietnam (they're the only ones that got to observe them).
I'm not entirely sure what you are asking but yes there was a trail, called the Ho Chi Minh trail, that ran partly through Laos and Cambodia to transport supplies and vietcong troops to south Vietnam.
The Ho Chi Minh Trail was a NETWORK than coursed through Laos and Cambodia.
Laos and Cambodia fell to communism.
From north to south, China, Laos, Cambodia.
Cambodia is located at the South East Asia. Next to Thailand, Vietnam, Laos. Upon China.