19 February Lieutenant General Nickerson and Lieutenant General Zais briefed General Abrams on the planned Army takeover of ICTZ on 9 March. Abrams sanctioned the arrangement proposed by Nickerson whereby III MAF, while becoming subordinate to XXIV Corps, still remained parent unit of 1st Marine Division and 1st Marine Aircraft Wing, preserving the integrity of the Marine air-ground team concept in Vietnam.
5-9 March During Operation Cavalier Beach, III MAF relocated to Camp Haskins and XXIV Corps moved from its headquarters in Phu Bai to Camp Horn.
9 March Lieutenant General Herman Nickerson, Jr., passed operational command of I Corps to Lieutenant General Melvin Zais, USA, and simultaneously passed command of III MAF to Lieutenant General Keith B. McCutcheon.
9 March III MAF turned command of I Corps over to XXIV Corps. Major elements of III MAF at the time included the 1st Marine Division (Rein), 1st MAW, and FLC-
19 March The 26th Marines, which had received a Presidential Unit Citation for the defense of Khe Sanh, departed Vietnam. Following the regiment's departure, the 1st Marines was left to control the Rocket Belt, an area of some 534 square kilometers.
19 March The U.S. said that its recognition of Cambodian sovereignty would continue following the seizure of power from Prince Norodom Si-hanouk by General Lon Nol.
26 March The Combined Action Force was placed under the operational control of XXIV Corps while remaining under the administrative control of III MAF.
April
During April the Marine Corps stopped taking draftees.
14 April Major General C. F. Widdecke relieved Major General Edwin B. Wheeler as Commanding General, 1st Marine Division, and as Deputy Commander, III MAF.
21 April President Thieu said that the Vietnamese could gradually assume greater responsibilities as the Americans withdrew from Vietnam but that the South Vietnamese would require more aid from allies.
23 April The 1st force Service Support Regiment was closed down and transferred to Camp Pendleton.
27 April Following a helicopter crash on 18 April Major General Edwin B. Wheeler, who broke a leg on impact, was replaced by Major General Charles F. Widdecke.
30 April President Nixon announced that several thousand American troops supporting the RVNAF invasion entered Cambodia's Fishook area bordering South Vietnam to attack the supposed location of the headquarters of the Communist military operation in South Vietnam. American advisors, tactical air support, medical evacuation teams, and logistical support were also provided to the RVNAF. On 9 May Brigade B of the VNMC crossed the Cambodian border and at 0930 landed at Neck Luong to begin operations. Allied troops in Cambodia increased to 50,000 by 6 May. Withdrawal of American units from Cambodia was completed when the 1st Cavalry Division (Airmobile) returned to South Vietnam on 29 June.
