The I Marine Amphibious Corps, or I MAC, was a formation of the United States Marine Corps.
It was created on 1 October 1942, with most of the staff transferred from Amphibious Corps, Pacific Fleet (ACPF). It was then deployed to the South Pacific Area – a U.S.-led multinational military command active during World War II that was a part of the U.S. Pacific Ocean Areas – first to Hawaii, then to New Caledonia.[1]
General Vandegrift carried on in command of the Corps when its next-designated commander for the invasion of Bougainville, Major General Charles D. Barrett, died following a fall from the balcony of his quarters in New Caledonia.[3] General Vandegrift led I MAC during the invasion and was later made the Commandant.
The Corps' insignia was a shield with a blue field emblazoned by the Southern cross constellation in white and a square red diamond outlined with a white border, center. Various elements of the Corps used this basic design with their task insignia in white on the red center.
^U.S. Marine Corps World War II Order of Battle – Ground and Air Units in the Pacific War, 1939–1945,Gordon L. Rottman (2001). Westport, Connecticut:Greenwood Press. p. 108. ISBN978-0-313-31906-8.