Both battalions of the 16th Infantry that were active at Fort Riley, KS, as of 1965 served admirably in the Vietnam conflict. The 2nd Battalion, 16th Infantry Regiment served in Vietnam from July 1965 to April 1970. The 1st Battalion served there from October 1965 to April 1970. The 1st Battalion underwent an organizational change in 1968 when it swapped colors with the 5th Battalion, 60th Infantry and became a mechanized infantry battalion, the first in the regiment’s history. During almost five years of combat, the 1st and 2nd Battalions earned the 16th Infantry Regiment no less than 11 campaign streamers, 2 Republic of Vietnam Cross of Gallentry (with Palm) Streamers, and a Republic of Vietnam Civil Action Streamer. Additionally, C Company, 2nd Battalion was awarded the Valorous Unit Citation for its actions at Courtenay Plantation in 1966.

Meanwhile, the Army Reserve’s 3rd Battalion in Massachusetts served as part of the 187th Infantry Brigade (Separate) and trained for, and stood ready in case of, a major conflict in Europe. Its mission was to deploy with the 187th Brigade to Iceland and defend that island in the event of war with the Soviet Union. In March 1970 both of the active battalions in Vietnam stood down from combat activities and prepared to leave for new missions. The 2nd Battalion was sent back to Fort Riley to be reorganized as a mechanized infantry battalion with the 1st Infantry Division (Mechanized), while the 1st Battalion was sent to a new assignment in Germany with the 1st Infantry Division (Forward).