The Battle of Dumpu was an action fought in September and October 1943 between Australian and Japanese forces in New Guinea during the Markham and Ramu Valley – Finisterre Range campaign of World War II. After the Battle of Kaiapit on 20 September 1943, in which the 2/6th Independent Company won a stunning victory against a numerically superior Japanese force, Ivan Dougherty's 21st Infantry Brigade of the 7th Division advanced from Kaiapit to Dumpu in the Ramu Valley. During the entire advance, the Australian and American forces in the Ramu Valley were supplied by air. The capture of the Ramu Valley allowed a forward airbase to be developed at Gusap.