HistoryData
Historical ConflictBougainville Island

Battle of the Coconut Grove

The Battle of the Coconut Grove secured a key trail intersection on Bougainville, enabling Allied airfield construction in support of Operation Cartwheel.

Duration & Scope

1943 ongoing

< 1 year

Key Facts

Dates
13–14 November 1943
Duration
2 days
US unit involved
21st Marine Regiment, USMC
Strategic objective
Clear Numa Numa Trail for airfield construction
Key terrain gained
Numa Numa and East–West Trails intersection

Strategic Narrative Overview

After consolidating the beachhead at Koromokina Lagoon and fighting along the Piva Trail, a Marine reconnaissance party identified airfield construction sites beyond the perimeter. Elements of the 21st Marine Regiment advanced to clear the Numa Numa Trail but were ambushed by Japanese forces. Over two days of close combat, Marines brought up reinforcements, sustaining pressure until the Japanese withdrew, ceding control of the strategically important trail intersection.

01 / The Origins

Following the Allied landings at Cape Torokina in early November 1943 as part of Operation Cartwheel, US forces established a beachhead on Bougainville Island. The broader campaign aimed to neutralise the major Japanese base at Rabaul by capturing territory within air-striking distance. Securing the beachhead and advancing inland was essential to constructing airfields that would extend Allied air power across the Solomon Islands theatre.

03 / The Outcome

By 14 November 1943, US Marines held the intersection of the Numa Numa and East–West Trails, opening the way for airfield construction outside the Bougainville perimeter. The Japanese withdrawal allowed Allied engineers to proceed with their plans. Fighting continued nearby at Piva Forks in the days immediately following, as US forces worked to expand and consolidate the defensive perimeter around the new beachhead.

Belligerents & Mobilization Analysis

Side A

1 belligerent

United States Marine Corps

Side B

1 belligerent

Imperial Japanese Army
Outcome
US Marine victory; Marines seized the Numa Numa–East–West Trails intersection, enabling airfield construction

Kinetic Engagement Axis

Major engagements timeline (1943–present)Timeline of major military engagements plotted chronologically.1943present1943Battle of the Co…Allied1943Battle of Piva F…

Scroll horizontally to view full axis. Events plotted relatively.

Side A victorySide B victoryInconclusiveDecisive / turning point

Location

Map of Papua New GuineaMap of Papua New GuineaPapua New Guinea