Battle of Edson's Ridge - Aftermath

Aftermath

At 13:05 on 14 September, Kawaguchi led the survivors of his shattered brigade away from the ridge and deeper into the jungle, where they rested and tended to their wounded all the next day. Kawaguchi's units were then ordered to withdraw west to the Matanikau River valley to join with Oka's unit, a 6 mi (9.7 km) march over difficult terrain. Kawaguchi's troops began the march on the morning of 16 September. Almost every soldier able to walk had to help carry the wounded. As the march progressed, the exhausted and hungry soldiers, who had eaten their last rations on 14 September, began to discard their heavy equipment and then their rifles. By the time most of them reached Oka's positions at Kokumbona five days later, only ½ still carried their weapons. The Kuma battalion's survivors, attempting to follow Kawaguchi's Center Body forces, became lost and wandered for three weeks in the jungle and almost starved to death before finally reaching Kawaguchi's camp.

In total, Kawaguchi's forces lost about 830 killed in the attack, including 350 in Tamura's battalion, 200 in Kokusho's battalion, 120 in Oka's force, 100 in the Kuma battalion, and 60 in Watanabe's battalion. A further but unknown number of wounded died during the withdrawal march to the Matanikau. On and around the ridge, the Marines counted 500 Japanese dead, including 200 on the slopes of Hill 123. The Marines suffered 80 killed between 12 and 14 September.

On 17 September, Vandegrift sent two companies from the 1st Battalion, 1st Marine Regiment (1/1) to pursue the retreating Japanese. The Marines were ambushed by two Japanese companies acting as rear-guards for the withdrawal, and one Marine platoon was pinned down as the rest of the Marines retreated. The Marine company commander requested permission to attempt to rescue his platoon but was denied by Vandegrift. By nightfall, the Japanese overran and nearly annihilated the platoon, killing 24 Marines with only a few wounded members of the platoon surviving. On 20 September, a patrol from Edson's Raiders encountered stragglers from Kawaguchi's retreating column and called in artillery fire that killed 19 of them.

As the Japanese regrouped west of the Matanikau, the U.S. forces concentrated on shoring up and strengthening their Lunga defenses. On 14 September, Vandegrift moved another battalion, the 3rd Battalion, 2nd Marine Regiment (3/2), from Tulagi to Guadalcanal. On 18 September, an Allied naval convoy delivered 4,157 men from the 3rd Provisional Marine Brigade (the U.S. 7th Marine Regiment augmented by additional support units) to Guadalcanal. These reinforcements allowed Vandegrift—beginning on 19 September—to establish an unbroken line of defense completely around the Lunga perimeter. Vandegrift's forces' next significant clashes with the Japanese occurred along the Matanikau River from 23–27 September and 6–9 October.