Ground Forces

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bigpigeon.us webpage WWII US > Ground Forces > Ground Forces - War with Japan, © 2025 by Robert A. Christiansen, updated by RAC 19 Feb 2025
​This webpage supports Big Pigeon's WWII Japan module, and is not entirely complete. It contains an order of battle summary for United States Army and Marine Corps ground forces in the War with Japan.

Part 1 - United States Armies, Corps and Divisions in the Pacific Theater in World War II
Part 1 excludes the Marine Corps.

                    ========== The United States fielded three armies in the Pacific Theater ==========
Sixth Army (Southwest Pacific, Krueger):

• Activated January 1943. Sixth Army forces were originally known as Alamo Force.
• Controlled SW Pacific land operations in New Guinea and the Bismarck Archipelago.
• Invaded Leyte, Philippine Islands October 1944 with X and XXIV Corps.
• Invaded Luzon, Philippine Islands at Lingayen Gulf 9 January 1944 with I and XIV Corps.

Eighth Army (Southwest Pacific, Eichelberger):

• 28 Sep–12 Oct 1944 - progressively assumed control of Sixth Army units in Australia, New Guinea, and Bismarck Archipelago.
• 13 Oct–15 Nov 1944 - relinquished combat responsibility in Aitape and New Britain to First Australian Army.
• Dec 1944 - assumed control of Leyte operations.
• Jan 1945 - invaded Luzon, Philippine Islands west and south of Manila 29/31 January 1944 with XI Corps and 11th Airborne Division; control of these units then passed to Sixth Army.
• Conducted the Southern Philippines Campaign for the remainder of WWII.
• Assumed control of combat operations on Luzon late in WWII.

​Tenth Army (Buckner/Geiger/Stilwell):

• Land invasion of the Ryukyu Islands, known as the battle of Okinawa, with XXIV Corps and III Marine Amphibious Corps.

                    ========== Six United States Army corps served in the Pacific Theater ========== 
I Corps:

• Apr 1944 - landed at Hollandia, Dutch New Guinea under control of Sixth Army.
• 15 Jun 1944 - assumed command of Hurricane Task Force on Biak Island, New Guinea.
• 29 Jun 1944 - relieved of command of Hurricane Task Force on Biak Island and returned to Hollandia area.
• 20 Nov 1944 - relieved of responsibility for defense of Hollandia area.
• 9 Jan 1945 - landed in Lingayen Gulf, Luzon.
• 30 Jun 1945 - relieved of responsibility for combat missions assigned to it.

IX Corps: (never saw combat)

• 17 Oct 1944: arrived Oahu. 
• 10 Jul 1945: arrived Leyte and assigned to Sixth Army.
• 11 Jul 1945: prepared plans for Operation Olympic, invasion of Kyushu, Japan.

​X Corps:

• 20 Oct 1944 - landed on Leyte under control of Sixth Army.
• 26 Dec 1944 - control passed from Sixth to Eighth Army.

XI Corps:

• 27 Jun 1944 - assumed command of Persecution Task Force in Aitape, New Guinea from 32nd Infantry Division.
• 25 Aug 1944 - command of Persecution Task Force returned to 32nd Infantry Division.
• 25 Sep 1944 - assumed command on Morotai, Dutch Indies.
• 26 Dec 1944 - control passed from Sixth to Eighth Army.
• 29–30 Jan 1945 - elements landed near Subic Bay on Luzon and control passed to Sixth Army.

XIV Corps:

• 9 Feb 1943 - assigned ISCOM Guadalcanal.
• 9 Jan 1945 - landed in Lingayen Gulf, Luzon.
• 1 Jul 1945 - control passed from Sixth Army to Eighth Army.

XXIV Corps:

• 8 Apr 1944 - activated on Oahu.
• 20 Oct 1944 - landed on Leyte.
• 1 Apr 1945 - landed on Okinawa.

         ========== The United States fielded the following divisions in the Pacific Theater ==========

• Philippines Division, aka 12th Infantry Division - destroyed in the 1942 Fall of the Philippines
• 6th Infantry Division - New Guinea, Luzon
• 7th Infantry Division - Aleutian Islands, Eastern Mandates, Leyte, Ryukyus
• 11th Airborne Division - New Guinea, Leyte, Luzon
• 23rd Infantry Division, AKA Americal Division - Guadalcanal, Northern Solomons, Leyte, Southern Philippines
• 24th Infantry Division - Central Pacific, New Guinea, Leyte, Luzon, Southern Philippines
• 25th Infantry Division - Guadalcanal, Northern Solomons, Central Pacific, Luzon
• 27th Infantry Division - Central Pacific, Western Pacific, Ryukyus
• 31st Infantry Division - New Guinea, Southern Philippines, Western Pacific
• 32nd Infantry Division - Papua, New Guinea, Leyte, Luzon
• 33rd Infantry Division - New Guinea, Luzon
• 37th Infantry Division - Northern Solomons, Luzon
• 38th Infantry Division - New Guinea, Leyte, Luzon
• 40th Infantry Division - Bismarck Archipelago, Luzon
• 41st Infantry Division - New Guinea, Luzon, Southern Philippines
• 43rd Infantry Division - Guadalcanal, Northern Solomons, New Guinea, Luzon
• 77th Infantry Division - Western Pacific, Leyte, Ryukyus
• 81st Infantry Division - Western Pacific, Leyte
• 93rd Infantry Division -Northern Solomons, Bismarck Archipelago, New Guinea
• 96th Infantry Division - Leyte, Ryukyus
• 1st Cavalry Division - New Guinea, Bismarck Archipelago, Leyte, Luzon

Notes on the above list:

• New Guinea includes Morotai, Dutch Indies.

Part 2 - Order of Battle for Different Stages of the War with Japan
Part 2 includes the Marine Corps.

              Pre-combat disposition of early US Army divisions in the South and Southwest Pacific
US Army Forces South Pacific & South Pacific Area Command (rear area, pre-combat)

• 23rd/Americal Infantry Division, Jul 1942-Jan 1943 (began arriving on Guadalcanal 12 Nov 1942)
• 37th Infantry Division, Sep 1942-Apr 1943

US Army Forces Australia (rear area, pre-combat)

• 32nd Infantry Division, May 1942-
• 41st Infantry Division, Apr 1942-

          ========== 1 - South Pacific (Ghormley/Halsey) & SW Pacific (MacArthur), 1942-44 ==========

                                             ===== Southeast New Guinea, Papua, 1942-43 =====
I Corps, from August 1942 (Eichelberger).

• 32nd Infantry Division, Sep 1942-
• 41st Infantry Division, Jan 1943-

                                    ===== Northeast New Guinea, Lae to Madang, 1943-44 =====
Sixth Army, AKA Alamo Force, from February 1943 (Krueger)
I Corps (Eichelberger).

• 32nd Infantry Division, Jan 1944-
• 41st Infantry Division, Dobodura/25 Jan 1943-

• ?24th Infantry Division (Aug 1943-Sep 1944)
• 503rd Parachute Infantry Regiment, Sep 1943 

                                                        ===== Western New Guinea,1944 =====
Sixth Army, AKA Alamo Force (Krueger)
I Corps (Eichelberger).

• 32nd Infantry Division, Apr 1944-
• 41st Infantry Division, Hollandia 22 Apr 1944, Biak 27 May 1944-

• 24th Infantry Division, Apr 1944-
• ? 503rd Parachute Infantry Regiment, Sep 1943 

XI Corps – from Mar 1944, New Guinea (Hall).

• 6th Infantry Division, Jul 1944/Sansapor
• 31st Infantry Division (elts.), Jul 1944/Driniumor River
• ? 32nd Infantry Division (Jun-Oct 1944)
• 33rd Infantry Division (elts.), Jan 1945/Morotai
• 43rd Infantry Division (Wing), 22 Jul 1945/Aitape

​
Eighth Army, from August 1944 (Eichelberger), 

South Pacific, Solomon Islands, 1942-?, 
XIV Army Corps – from Dec 1942, initially under Navy or Marine Corps control. (Patch, Griswold).
Guadalcanal:

• 23rd/Americal Infantry Division, Nov 1942 
• 25th Infantry Division, Jan 1943
• 2nd Marine Division
• 147th Infantry Regiment, Nov 1942

New Georgia:

• 25th Infantry Division
• 37th Infantry Division, Jul 1943
• 43rd Infantry Division (Hester, Wing), 30 Jun 1943-

Bougainville:

• 37th Infantry Division, Nov 1943
• 23rd/Americal Division, Dec 1943
• 93rd Infantry Division, Mar 1944

                                               2 - ========== North Pacific, 1943 ==========

• 7th Infantry Division, Attu (Brown)

                                          3 - ========== Central Pacific, 1943-44 ==========

​Gilbert Islands, 1943, V USMC Amphibious Corps. (Holland Smith)

• 2nd Marine Division, Tarawa, 20-23 November 1943
• 27th Infantry Division, Makin, 20-23 November 1943 (Ralph Smith)

Marshall Islands, 1943-44.
Kwajalein Atoll, 31 Jan-3 February 1943, V USMC Amphibious Corps (Holland Smith)

• 4th Marine Division
• 7th Infantry Division

Eniwetok Atoll, 17-23 February 1943

• 22nd Marine Regiment
• 106th Infantry Regiment​

Saipan, Mariana Islands, 1944, V USMC Amphibious Corps. (Holland Smith)

• 2nd Marine Division
• 4th Marine Division
• 27th Infantry Division (Ralph Smith)
• 147th Infantry Regiment

Guam, Mariana Islands, 1944, III USMC Amphibious Corps. (Geiger)

• 3rd Marine Division
• 1st Provisional Marine Brigade
• 77th Infantry Division (Bruce), 21 Jul 1944-

Tinian, Mariana Islands, 1944, V USMC Amphibious Corps. (Holland Smith)

• 4th Marine Division
• 2nd Marine Division
• 147th Infantry Regiment.

​Palau Islands, 1944.
III USMC Amphibious Corps. (Holland Smith)

• 1st Marine Division, Pelelieu (Rupertus)
• 81st Infantry Division, Angaur, 17 Sep 1944- & Pelelieu, 19 Oct 1944-  (Mueller)

                         4 - ========== The Philippines Liberated (MacArthur), 1944-45 ==========

Army & Corps Organization, Philippines, 1944-45. (perhaps delete)
6th Army (Krueger) (8th Army assumed responsibility 1 Jul 1945.)

• I Army Corps –Luzon (Swift).
• X Army Corps – Leyte, southern Philippines (Sibert).
• XIV Army Corps – Luzon (Griswold).
• XXIV Army Corps – Leyte (Hodge). (after Leyte, transferred to Tenth Army for Battle of Okinawa)

8th Army (Eichelberger)

• XI Army Corps – Luzon, southern Philippines (Hall)
• XIV Army Corps – Luzon (Griswold).

Leyte Campaign, Sixth Army, 20 October 1944 -->26 December 1944 (Krueger)  
X Army Corps, 20 Oct 1944 -->26 Dec 1944 8th Army (Sibert)

• 24th Infantry Division (landing participant, Sep 1944-)
• 32nd Infantry Division (landed 14 November)
• 1st Cavalry Division (landing participant)
• 112th Cavalry Regimental Combat Team

XXIV Army Corps, 20 Oct 1944 (Hodge).

• 7th Infantry Division (landing participant)
• 96th Infantry Division (landing participant, 20 Oct 1944-)
• 77th Infantry Division, 23 Nov 1944-
• 11th Airborne Division (reserve)

Control of Leyte & Samar passed to Eighth Army, 26 December 1944 (Eichelberger)

Luzon Campaign, Sixth Army, 9 Jan 1945 --> 1 July 1945 (Krueger)
I Army Corps (Swift), landing at Lingayen Gulf

• 6th Infantry Division (landing participant, to XIV Corps 17 February 1945)
• 25th Infantry Division
• 32nd Infantry Division
• 33rd Infantry Division
• 43rd Infantry Division (Wing), landing participant, 9 Jan 1945-
• 158th Regimental Combat Team

XIV Army Corps (Griswold), landing at Lingayen Gulf

• 6th Infantry Division (from I Corps 17 February 1945)
• 37th Infantry Division (landing participant)
• 40th Infantry Division (landing participant)
• 1st Cavalry Division
• 11th Airborne Division

XI Corps (Hall), landing at Vigan? ( XI Corps control passed from 8th Army to 6th Army on 30 January.)

• 34th Infantry Regiment < 24th Inf. Div., landing participant, 29 Jan 1945-
• 38th Infantry Division, landing participant, 29 Jan 1945-
• 1st Infantry Regiment < 6th Inf. Div., ~ 14 Feb 1945-

Luzon Campaign, latter stages Eighth Army, 1 July 1945 --> 15 August 1945 (Eichelberger) 
XI Corps (Hall)

• 23rd Infantry Division
• 31st Infantry Division
• 38th Infantry Division
• 41st Infantry Division
• 93rd Infantry Division
• 503rd Parachute Infantry Regiment

XIV Corps, Northern Luzon, from Sixth Army 1 July 1945 (Griswold)

• 6th Infantry Division
• 32nd Infantry Division
• 37th Infantry Division
• 38th Infantry Division

Southern Philippines Campaign, 27 Feb - 4 Jul 1945, 8th Army (Eichelberger).
X Army Corps, Mindanao, 17 Apr 1945 – 30 Jun 1945 (Sibert).

• 24th Infantry Division, Parang, 17 Apr 1945
• 31st Infantry Division, 22 Apr 1945
• 162nd RCT (from 41st Infantry Division), Zamboanga City, 10 Mar 1945
• 163rd RCT (from 41st Infantry Division), Zamboanga City, 10 Mar 1945
• 186th RCT (from 41st Infantry Division), Panay Is.
• 108th RCT (from 40th Infantry Division)

XI Army Corps (Hall) (some units also served on Luzon)

• 23rd Infantry Division (a.k.a. Americal Division)
• 31st Infantry Division  (Mindanao 22 Apr 1945)
• 41st Infantry Division Palawan 28 Feb 1945 & Mindanao)
• 93rd Infantry Division (African-American)
• 503rd Parachute Infantry Regiment
• 38th Infantry Division

                                       5 - ========== Iwo Jima & Okinawa, 1945 ==========

Battle of Iwo Jima, 19 February 1945 
V USMC Amphibious Corps (Holland Smith & Schmidt).

• 3rd Marine Division
• 4th Marine Division
• 5th Marine Division
• 147th Infantry Regiment, Mar 1945

Ryukyu Islands Campaign, aka Okinawa, 26 March-2 July 1945, 10th Army (Buckner/Geiger/Stilwell).
XXIV Army Corps (Hodge)

• 7th Infantry Division
• 27th Infantry Division
• 77th Infantry Division, 26 Mar 1945-, 16 Apr 1945-, 27 Apr 1945
• 96th Infantry Division, 1 Apr 1945-

III USMC Amphibious Corps (Geiger)

• 1st Marine Division
• 2nd Marine Division
• 6th Marine Division
• 147th Infantry Regiment​