The Vietnam War occured from 1959- April 30, 1975. U.S. became involved in Vietnam in 1950 to assist the French colonial forces. Forces entered Vietnam to overthrow President of South Vietnam Ngo Dinn Diem when he declined to hold elections.

The Vietnam conflict involved clashes between small units patrolling the mountains and jungles, amphibious operations, guerrilla attacks , and cities and large conventional battles. U.S. aircraft also conducted massive aerial bombing, targeting North Vietnam's cities, industries and logistical networks. Later Cambodia and Laos were drawn into the conflict. Large quantities of chemical defoliants were sprayed from the air, to reduce the cover ares available to the enemy.