Established 1 Oct. 1942. Action on Guadalcanal, Russell Islands, New Georgia, Bougainville, and Emirau. All 1st MAC assets were assigned to the III Amphibious Corps 15 April 1944.
Forces included Supply units, 1st Corps Signal, Motor Transport and Medical Battalions. Elements moved forward with the Marine advances across the pacific and ensured support of the combat effort.
Composed of the 1st and 2nd Aviation Engineer Battalions. The first was attached to 1st Marine Aircraft Wing. The 2nd was deployed to Guadalcanal in 1943 and worked on Koli 1 & 2 airfields, bomb dump and dock areas. Transfered to III Amphib Corps in 1944.
A total of 6 Barrage Ballon squadrons were activated in WWII, and were organized into 4 sections with 6 ballons per section. the 2nd & 4th squadrons were assigned on American Samoa, with the 1st, 3rd, 5th, and 6th were at Noumea, New Calidonia. Eventually this mission was turned over to the Army and the majority of the Marines were assigned to Defense Battalions.
Based on one of the Marines basic missions: "To assist the Fleet in the seizure and initial defense of such advanced bases as the fleet may require in its war operations." The 1st through 7th Defense Battalions were assigned through out the American sphere of influence with two of particular interest, The 5th was on Iceland and another detachment on Wake. (See bio on Major J. Devereux.) A total of 20 Def. Bns. were eventually raised, but not all served w/ the 1st MAC. Starting in 1944 all Def. Bns. were redesignated as antiaircraft units.
Parachute units assigned to 1st MAC were the 1st, 2nd, and 3rd Parachute ans. which were combined into the First Parachute Regiment on 1 April 1943. While participating in several bloody actions during the course of the war, they were utilized as infantry and there were no Marine parachute combat jumps during W.W.II, as a result of lack of transport, long distances, and the fact that Marines were generally assigned to attack small heavily defended islands which were not suitable for para type operation.
While not a Marine Corps patch, often Sailors attached to Marine units wore Marine Corps uniforms with Naval designation for Rate & Rank.
Organized in Apr. 1944 of elements of the 1st MAC to direct the operation of two Marine Amphibious Corps in the pacific theater. The combat elements of 1st MAC fell under IIIAC while a short time later, the administrative and support elements came under the purview of FMFPAC. Elements of this unit fought on Saipan, Tinian, Guam, Peleliu, and Okinawa. Following the Japanese surrender this Corps saw occupation duty in Northern China in Oct. 1946, as Marine Forces China.
Established 4 Sept. 1943 from the redesignated Headquarters, Amphibious Corps Pacific Fleet, as a augment to the 5th Fleet and Central Pacific Force Naval commands. This unit was tasked the mission of combining and directing Marine Corps and Army amphibious assaults. VAC units went ashore on Tarawa and the Army assault of Makin Island. (Not the Raider mission of earlier in the war.) Additional action was seen at Kwajalein, Eniwetok, the Marianas, Saipan, Tinian, Guam, the Philippines, Iwo Jima, and the occupation of Japan.