Vietnam War: U.S. military personnel by branch of service 1964-1975

The United States' war in Vietnam was its largest direct conflict during the period known as the Cold War. Approximately 40 percent of the entire U.S. military served in Southeast Asia over the course of the Vietnam War, and over 75 percent of these served directly in South Vietnam. The conflict was central to U.S. anti-communist foreign policy during this period, however the U.S. maintained a significant military presence in strategic regions across the globe, such as West Germany, Taiwan, and South Korea.
The Army and Marine Corps were represented in Southeast Asia and South Vietnam in greater proportion than in the U.S. military overall. The Army made up around two-thirds of the personnel serving in Vietnam, while being approximately half of the total U.S. servicemembers during this period.