bigpigeon.us webpage WWII-Japan > South & SW Pacific, © 2023 by Robert A. Christiansen, updated by RAC 4 Jan 2023.
Links to WWII-Japan > South & SW Pacific subpages follow this introductory material.
The US offensive land operations in the South and Southwest Pacific Areas ...
  • ... began in the summer of 1942 with the US Marine Corps invasion of the Guadalcanal area in the Solomon Islands and Australian and US Army forces pushing back Japanese advances in southeast New Guinea.
  • ​... ended in September 1944 with the US Army invasion of Morotai in the Dutch Indies, 2,300 miles to the northwest. 
1942-44 US Path Across the Southwest Pacific
1942-1944 US Path Across the Southwest Pacific
These operations, as with most Pacific Area offensive operations, began with amphibious landings and required major assistance from the US Navy. In particular, the Guadalcanal land campaign was coupled with a series of massive sea battles.
Links to Big Pigeon's South Pacific Area (SPA) & Southwest Pacific Area (SWPA) subpages
Southwest Pacific Area - 1942
Southwest Pacific Area - 1942
  • The South Pacific Area (SPA), US Navy controlled, was commanded by Admiral William Halsey from 19 October 1942 to May 1944 , with initial headquarters in Noumea, New Caledonia.
  • The Southwest Pacific Area (SWPA), US Army controlled, was commanded by General Douglas MacArthur, with initial headquarters in Brisbane, Australia.
In the above list of links, I have indicated, where appropriate, which command was in charge.
South Pacific Area
South Pacific Area
I view the complex Allied ground offensive in the South and Southwest Pacific from 1942 through the summer of 1944 as consisting of three chronological phases, each with a different goal.
Phase 1, Protecting Australia, July 1942 – February 1943
In early 1942, as Japanese forces moved with little effective opposition into the southern Pacific, concern grew that lines of commerce between North America and Australia might be broken, that Australia might come under attack, or even that the Australian future might include a Japanese invasion.

In May and June of 1942, Japan's sea-borne attempts to greatly advance the boundaries of the Japanese Empire were thwarted at the battles of the Coral Sea and Midway. Subsequently, Japan began smaller-scale advances in Papua in southeastern New Guinea and in the Guadalcanal Island area in the Solomon Islands. 

These small-scale Japanese offensives were thwarted in late 1942 by two parallel and lengthy Allied land offensives:
  • In Papua, Southeast New Guinea, by Australian and US forces pushing back the Japanese.
  • In the southern Solomon Islands, by US forces driving the Japanese from the Guadalcanal area.
During Phase 1,  the main US ground contributions were:
  • participating with Australian forces in Papua in operations that cumulated with the Battle of Buna-Gona in Papua.
  • driving Japanese forces from Guadalcanal in the Solomon Islands.

​Phase 1 included vicious sea battles in the Solomon Islands area, during which US naval deaths far exceeded those on the ground.
S & SW Pacific - Phases 1 & 2
S & SW Pacific, Phases 1 & 2 - Eastern New Guinea, Solomon Islands, & Bismarck Archipelago
Phase 2, Operation Cartwheel, Isolating Rabaul, the main Japanese base, April 1943 - April 1944
Rabaul is on the north end of New Britain Island in the Bismarck Archipelago. Rabaul had been captured from Australian militia forces early in 1942.

Rabaul was well-located with a suburb harbor and protected by multiple air fields. 
​
Most ground combat during Phase 2 operations was handled by Australian forces in northeast New Guinea and US forces in the Bismarck Archipelago and the Solomon Islands. 
S & SW Pacific, Phase 2, Cartwheel
S & SW Pacific, Phase 2, The Operation Cartwheel Area
The key to isolating Rabaul was to develop a ring of secure Allied air bases within easy striking distance of Rabaul.

As Phase 2 drew to a close, 
  • Marine Corps forces were withdrawn to use in the Central Pacific Campaign, which began in November 1943 with the invasion of the Gilbert Islands.
  • Australian forces were relieved from offensive operations to perform occupation duties and begin preparing for future landings in the Dutch Indies.
300-Mile Radius from Rabaul
300-Mile Radius from Rabaul
Phase 3, Advancing towards the Philippines, April-September 1944
Phase 3, the advance westward along the north coast of New Guinea, was implemented by MacArthur’s Southwest Pacific Area forces. Landings are shown on the accompanying map. Phase 3 ended with a landing on the island of Morotai in the Dutch Indies. 
S & SW Pacific Western New Guinea
South & SW Pacific, Phase 3 - Western New Guinea
​Sources for Big Pigeon's WWII-Japan > South & Southwest Pacific webpage:
  • The 1942 - 1944 US Path Across the Southwest Pacific map is taken from google.com.
  • The Southwest Pacific Area - 1942 map - https://www.ibiblio.org/hyperwar/USA/USA-C-Papua/index.html. 
  • The South Pacific Area map - https://www.ww2places.qld.gov.au/south-west-pacific-campaign#gallery-51274-17.
  • The New Guinea Area map is courtesy of history.army.mil.
  • I constructed the 300-Mile Radius from Rabaul map using www.calcmaps.com.
  • The Rabaul - Harbor & Airfields - WW II map - https://commons.wikimedia.org/wiki/File:Rabaul_-_map.jpg.