What was the name of the series of military operations during the Vietnam War in which U. S. Forces went into one of Vietnam's neighbor countries to fight?

The name of these operations was The Cambodian Campaign (also known as the Cambodian Incursion or Cambodian Invasion).

These military operations were conducted in eastern Cambodia in the year 1970. They were joint operations of the United States and the Republic of Vietnam (South Vietnam). There were 13 of them and they were considered an extension of the Vietnam war and the Cambodian Civil War.

The objection of these operations was the defeat of troops of People's Army of Vietnam and the Viet Cong in the eastern border regions of Cambodia. This region was considered a safe zone for Vietnamese communist forces. The Cambodian Campaign was deemed as highly successful by president Nixon.

Cambodian Incursion