Guadalcanal campaign
Edson, along with Colonel Gerald C. Thomas, Vandegrift's operations officer, thought that the Japanese attack would come at a narrow, grassy, -long, coral ridge south of Henderson Field. The ridge, called Lunga Ridge, had a good approach to the airfield and it was undefended. On 11 September, the 840 men of Edson's battalion were sent onto and around the ridge.