bigpigeon.us webpage WWII Japan > Order Of Battle > OOB - Divisions, © 2024 by Robert A. Christiansen, updated by RAC 20 Apr 2024. 
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The US Army and Marine Corps Divisions involved in the Pacific Area in the War with Japan
See also WWII Japan > Order of Battle > OOB - Armies & Corps.​​
The US Army Divisions in the Pacific Theater, their area & campaign participation, and their losses:
  • Philippines Division, aka 12th Infantry Division: destroyed in the 1941-42 Philippine Islands campaign. SWPA; dead count unknown.
  • 6th Infantry Division: SWPA > New Guinea, Luzon; 517 dead.
  • 7th Infantry Division: NPA > Aleutian Islands, CPA > Eastern Mandates; SWPA > Leyte; CPA > Ryukyus; 2,337 dead.
  • 11th Airborne Division - SWPA > New Guinea, Leyte, Luzon; 620 dead.
  • 23rd Infantry Division, aka Americal Division: SPA > Guadalcanal, Northern Solomons; SWPA > Leyte, Southern Philippines; 1,168 dead.
  • 24th Infantry Division - CPA > Central Pacific; SWPA > New Guinea, Leyte, Luzon, Southern Philippines; 1,691 dead.
  • 25th Infantry Division: CPA > Central Pacific; SPA: Guadalcanal, Northern Solomons; SWPA > Luzon; 1,500 dead.
  • 27th Infantry Division - CPA > Central Pacific, Western Pacific, Ryukyus; 1,849 dead.
  • 31st Infantry Division: SWPA > New Guinea, Southern Philippines; CPA > Western Pacific; 414 dead.
  • 32nd Infantry Division: SWPA > Papua, New Guinea, Leyte, Luzon; 2,002 dead.
  • 33rd Infantry Division: SWPA > New Guinea, Luzon; 524 dead.
  • 37th Infantry Division: SPA > Northern Solomons; SWPA > Luzon; 1,348 dead.
  • 38th Infantry Division: SWPA > New Guinea, Leyte, Luzon; 785 dead.
  • 40th Infantry Division: SWPA > Bismarck Archipelago, Luzon, Southern Philippines; 748 dead.
  • 41st Infantry Division: SWPA > New Guinea, Luzon, Southern Philippines; 962 dead.
  • 43rd Infantry Division: SPA > Guadalcanal, Northern Solomons; SWPA > New Guinea, Luzon; 1,414 dead.
  • 77th Infantry Division: CPA > Western Pacific, Ryukyus; SWPA > Leyte; 1,857 dead.
  • 81st Infantry Division: CPA > Western Pacific; SWPA > Leyte; 517 dead.
  • 93rd Infantry Division (colored): CPA > Northern Solomons; SWPA > Bismarck Archipelago, New Guinea.
  • 96th Infantry Division: SWPA > Leyte; CPA > Ryukyus; 2,038 dead.

1st Cavalry Division: SWPA > New Guinea, Bismarck Archipelago, Leyte, Luzon; 971 dead.
  • 26 Jul 1943 - arrived Straithpine, Queensland, Australia, north of Brisbane; assigned to Sixth Army.
  • 21 Dec 1943 - arrived Oro Bay, New Guinea.
  • 25 Feb 1944 - attached to Brewer Task Force as the major unit.
  • 29 Feb 1944 - elements of Brewer Task Force begin invasion of Admiralty Islands.
  • 18 May 1944 - Brewer Operation officially terminated.
  • 1 Oct 1944 - assigned to X Corps.
  • 20 Oct 1944 - landed on east coast of Leyte near Tacloban as right flank division of X Corps.
  • 26 Dec 1944 - assigned to Eighth Army.
  • 9–23 Jan 1945 - prepared for movement to Luzon Campaign.
  • 26 Jan 1944 - landed on Lingayen Gulf, Luzon.
  • 27 Jan 1945 - assigned to Sixth Army.
  • 31 Jan 1945 - assigned to XIV Corps.
  • 15 Jun 1945 - assigned to XI Corps.
  • 26 Jun–15 Aug 1945 - prepared for invasion of Japan.
  • 15 Aug 1945 - assigned to Eighth Army.
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​The United States Marine Corps six divisions in WWII, all of which fought only in the Pacific Theater:
  • First Marine Division: SPA > Guadalcanal; SWPA > Bismarck Archipelago > Cape Gloucester; CPA > Western Pacific, Ryukyus.
  • Second Marine Division: SPA > Guadalcanal; CPA > Central Pacific, Western Pacific, Ryukyus (8th Marine Regiment only).
  • Third Marine Division: SPA > Northern Solomons; CPA > Western Pacific, Iwo Jima.
  • Fourth Marine Division: CPA > Eastern Mandates, Western Pacific, Iwo Jima.
  • Fifth Marine Division: CPA > Iwo Jima; 2,501 dead.
  • Sixth Marine Division: CPA > Ryukyus.

Content after division names indicate area in which division participated as well as campaign names:
  • SWPA - Southwest Pacific Area (MacArthur).
  • SPA - participated in South Pacific Area (Ghormley, Halsey).
  • NPA - North Pacific Area, i.e., Alaska and the Aleutian Islands.
  • CPA - Central Pacific Area (Nimitz).
Further commentary on areas and campaigns.
  • I treat all of the Solomon Islands as being in the South Pacific Area even though geographically they mostly lay in the Southwest Pacific Area.
  • I incorporate Morotai in the Dutch Indies as part of the New Guinea Campaign.
  • The Eastern Mandates campaign refers to the Marshall and Gilbert Islands.
  • The Western Pacific campaign refers to the Mariana and Palau Islands.
Relationship between areas and campaigns:
  • Central Pacific Area > Central Pacific (Hawaiian & Gilbert Islands), Eastern Mandates (Marshall Islands), Western Pacific (Mariana & Palau Islands), Ryukyus.
  • Iwo Jima is not listed among Army campaigns.
  • South Pacific Area > Guadalcanal, Northern Solomons.
  • Southwest Pacific Area > Papua, New Guinea, Bismarck Archipelago, Leyte, Luzon, Southern Philippines.
​Sources for Big Pigeon's WWII Japan > Order of Battle > OOB - Divisions webpage: