Pacific Ocean Areas was a major Allied military command in the Pacific Ocean theater of World War II. It was one of four major Allied commands during the Pacific War, and one of three United States commands in the Asiatic-Pacific Theater. Admiral Chester W. Nimitz of the U.S. Navy, Commander in Chief, U.S. Pacific Fleet, headed the command throughout its existence.
The vast majority of Allied forces in the theatre were from the U.S. Navy, U.S. Army and U.S. Marine Corps. However units and/or personnel from New Zealand, the United Kingdom, Australia, Canada, Mexico, Fiji and other countries also saw active service.
On 24 March 1942, the newly formed British and US Combined Chiefs of Staff issued a directive designating the Pacific theater an area of American strategic responsibility. On 30 March the US Joint Chiefs of Staff (JCS) divided the Pacific theater into three areas: the Pacific Ocean Areas (POA), the South West Pacific Area (SWPA), and the Southeast Pacific Area. Details and transition, including whether Nimitz "appointed" or "nominated" the commander of the South Pacific Area, were worked out between 3 April and formal assumption of the overall Commander-in-Chief Pacific Ocean Areas by Nimitz on 8 May 1942.
The JCS designated Admiral Chester W. Nimitz as Commander in Chief, Pacific Ocean Areas (CINCPOA), with operational control over all units (air, land, and sea) in that area. The theater included most of the Pacific Ocean and its islands, but mainland Asia was excluded from the POA, as were the Philippines, Australia, the Netherlands East Indies, the Territory of New Guinea (including the Bismarck Archipelago) and the western part of the Solomon Islands. US strategic bomber forces in the theatre were under the direct control of the US Joint Chiefs of Staff. All land forces in Alaska and Canada remained under the control of the US Army's Western Defense Command (see Aleutian Islands Campaign).
The Joint Chiefs further divided the Pacific Ocean Areas into the North, Central and South Pacific Areas. Nimitz designated subordinate commanders for the North and South Pacific Areas (NORPAC and SOPAC) but retained the Central Pacific Area (CENPAC), including the Hawaiian Department, under his direct command.
From 1942-1943, three Army infantry divisions (23rd/"Americal", 25th, 27th) and two Marine divisions (1st, 2nd) fought in the POA (the 1st and 3rd Marine Divisions also fought in the SWPA in 1943). From 1944-1945, five Army infantry divisions (7th, 27th, 77th, 81st, 96th) and six Marine divisions (1st, 2nd, 3rd, 4th, 5th, 6th) served in the POA (an additional 15 Army divisions fought in the SWPA during this time). Among allied land force formations was the 3rd New Zealand Division, which fought in the Solomon Islands campaign during 1943-44.
In the separate South West Pacific Area, General Douglas MacArthur assumed command. The effective result of this organizational scheme was the creation of two separate commands in the Pacific: POA and SWPA, each reporting separately to the Joint Chiefs, each competing for scarce resources in an economy-of-force theater, and each headed by a commander in chief (CINC) from a different service. In particular, the division of the Solomons caused problems, since the battles of the Solomon Islands campaign in 1942-1943 ranged over the whole region, with the main Japanese bases in SWPA and the main Allied bases in SOPAC.