This narrative chronicles the activities of the U.S. Marine Corps in Southeast Asia from January 1961 to March 1965. The period witnesses increasing Marine Corps involvement in the region as our nation’s leaders responded to Communist aggression and sought to protect the United States’ national interests. Individual Marines saw duty as early as 1954 when a Marine lieutenant colonel was assigned to the U.S. Military Assistance Advisory Group (MAAG) in Saigon, South Vietnam. The first involvement of a Marine Corps operational unit came in March 1961 with the deployment to Udorn, Thailand, of approximately 300 Marines from Marine Air Base Squadron 16 (MABS16). The squadron’s mission was to provide aircraft maintenance and flight-line support operations for Air America, a U.S. company flying missions in support of the pro-Western forces in Laos. MABS-16 remained in northeast Thailand for seven months, not returning to its home base at Futema, Okinawa, until Air America had become self-supporting in October 1961.