OOB - Southwest Pacific - Big Pigeon in Southwest Iowa

South & SW Pacific

bigpigeon.us webpage WWII Japan > Order of Battle > OOB - Southwest Pacific, © 2024 by Robert A. Christiansen, updated by RAC 16 Mar 2024.

This webpage provides an organizational context to the US Army and Marine Corps ground war fought against Japan in New Guinea and the Bismarck Archipelago areas of the Southwest Pacific in 1942–44.

Allied operations in the Southwest Pacific Area were under the command of US General Douglas MacArthur, based in Brisbane, Australia. Ground operations by Australian and New Zealand forces are not shown on the heading map and not included in webpage text.

Relevant webpages in Big Pigeon's WWII Japan module:

Southeast New Guinea, Papua (July 1942–January 1943)
Northeast New Guinea, Lae to Madang (April 1943–April 1944)
The Bismarck Archipelago (December 1943–April 1944)
Western New Guinea (April 1944–September 1944)

During the first two phases of Allied combat in New Guinea, most ground action was by Australian troops.

Southeast New Guinea, Papua
I Corps (Eichelberger)

32nd Infantry Division (Harding): 19 November 1942–January/February 1943.
41st Infantry Division (Fuller) (elts.): 8 Jan 1943–

Northeast New Guinea, Lae to Madang
I Corps (Eichelberger)

41st Infantry Division (Fuller) : 30 June–October 1943; landing at Nassau Bay and fought in Salamaua area.
503rd Parachute Regiment: parachute landing at Nadzab northwest of Lae 5 September 1943–January 1944.

New Guinea in World War II

The Bismarck Archipelago
Battle of Arawe, Western New Britain Is., 15 December 1943–4 February 1944

112th Cavalry Regimental Combat Team (sep.) (Cunningham): 15 December 1943–8 June 1944
158th Infantry Regiment (sep., elts.): 27 Dec 1943–27 January 1944
40th Infantry Division (elts.): April 1944–

Battle of Cape Gloucester, Western New Britain Is., 26 December 1943–16 January 1944 - Operation Backhander

1st Marine Division (Rupertus): 26 December 1943–23 April 1944
40th Infantry Division (Brush): April 1944–

Commentary: Battle of Cape Gloucester:

After the battle officially concluded, combat in the area continued, including an amphibious landing in the Volupai–Talsea area about 100 miles to the east on 6 March 1944.
The departure of the 1st Marine Division from Cape Gloucester on 23 April 1944 marked the end of Marine Corps infantry involvement in the Southwest Pacific Area.

The Admiralty Islands: 29 February–18 May 1944 - Operation Brewer

1st Cavalry Division (Swift):

Western New Guinea
Battle of Hollandia, I Corps (Eichelberger): 22 April–6 June 1944 - Operation Reckless

24th Infantry Division (Irving): 22 April 1944–
41st Infantry Division (Fuller): 22 April 1944–

Commentary: Battle of Hollandia - Operation Reckless

Invasion of Aitape - first stage of Operation Persecution

41st Infantry Division > 163rd RCT: 22 April 1944–4 May 1944
32nd Infantry Division (Gill): 4 May 1944–

Commentary: Invasion of Aitape - first stage of Operation Persecution

Wadke-Maffin Bay Area
Capture of Wadke Islands:

41st Infantry Division > 163rd RCT: 17–19 May 1944

Perimeter defense and Battle of Lone Tree Hill:

158th RCT (sep.): 21 May–22 June 1944
6th Infantry Division (Sibert): 5 June–12 July 1944.

Subsequent perimeter defense:

31st Infantry Division (-) (Persons): 14 July–September 1944
33rd Infantry Division > 123rd Infantry Regiment: 1 September 1944–26 January 1945

Geelvink Bay Area
Battle of Biak Island, 27 May–17 August 1944

41st Infantry Division (Fuller, Doe): 27 May 1944–
24th Infantry Division > 34th Infantry Regiment: 18 June 1944–

Battle of Noemfoor Island, 2 July–31 August 1944 - Operation Cyclone

158th RCT (sep.): 2 July 1944–
503rd Parachute Regiment (sep.): parachute landing 3 July–9 November1944.

Battle of the Driniumor River, 10 July-25 August 1944 - second stage of Operation Persecution
XI Corps (Hall) assumed Aitape area command 27 Jun 1944–

112th Cavalry Regimental Combat Team (sep.) (Cunningham): 10 July 1944–
31st Infantry Division > 124th Infantry: 13 July–11 September 1944

Vogelkop Peninsula Operations, 30 July-31 August 1944

6th Infantry Division (Hurdis)

Morotai Island, Netherlands East Indies, 15 September-4 October 1944
XI Corps (Hall)

31st Infantry Division (Martin): 15 September 1944–
32nd Infantry Division > 126th Infantry Regiment: 16 September–9 November 1944
93rd Infantry Division (colored) (Johnson): 5 April 1945–

Sources for Big Pigeon's Order of Battle - Southwest Pacific webpage:

the page header map South & SW Pacific, https://mapsontheweb.zoom-maps.com/post/119343335279/the-new-guinea-area-1942-1944, is courtesy of the online content hosting site imgur.com.