The Kokoda Trail was a path that linked Ower's Corner, approximately 40 km north-east of Port Moresby, and the small village of Wairopi, on the northern side of the Owen Stanley mountain range. From Wairopi, a crossing point on the Kumusi River, the Trail was connected to the settlements of Buna, Gona and Sanananda on the north coast. Its name was derived from the village of Kokoda that stood on the southern side of the main range and was the site of the only airfield between Port Moresby and the north coast.
Having had their initial effort to capture Port Moresby by a seaborne landing disrupted by the battle of the Coral Sea, the Japanese saw the Kokoda Trail as a means by which to advance on it overland. Troops of the South Seas Detachment began landing at Gona on 21 July 1942, intending initially just to test the feasibility of the Kokoda Trail as a route of advance, but a full-scale offensive soon developed. The first fighting occurred between elements of the Papuan Infantry Battalion and the 39th Australian Infantry Battalion at Awala on 23 July. Although steadily reinforced by the battalions of 30th and 21st Brigades, the Australian force was unable to hold back the Japanese. It was poorly equipped, had not yet developed effective jungle warfare tactics, and was fighting at the end of a very long and difficult supply line. A number of desperate delaying actions were fought as the Australians withdrew along the Trail. They finally stopped on 17 September at Imita Ridge, the last natural obstacle along the Trail, a mere 8 km from the junction with the road to Port Moresby. The Japanese held the opposite ridge, 6 km distant at Ioribaiwa.
The tactical situation, however, had now swung in favour of the Australians. Their artillery at Ower's Corner was now in range and their supplies could be trucked most of the way forward; whereas Japanese supplies had to be carried all the way from the north coast. As a result of severe losses suffered by the Japanese on Guadalcanal following the American landing there, the South Seas Detachment was ordered to withdraw to the north coast of Papua and establish a defensive position there. Australian troops of the 25th Brigade began to edge forward from Imita Ridge on 23 September; the Japanese withdrew from Ioribaiwa the next day. In the course of their retreat the Japanese fought delaying actions every bit as determined as those of the Australians. Several difficult and costly battles were fought before the 16th and 25th Brigades crossed the Kumusi at Wairopi in mid-November heading for even more bitter fighting around the Japanese beachheads at Gona, Buna and Sanananda.
The Kokoda Trail fighting was some of the most desperate and vicious encountered by Australian troops in the Second World War. Although the successful capture of Port Moresby was never going to be precursor to an invasion of Australia, victory on the Kokoda Trail did ensure that Allied bases in northern Australia, vital in the coming counter-offensive against the Japanese, would not be seriously threatened by air attack. Approximately 625 Australians were killed along the Kokoda Trail and over 1,600 were wounded. Casualties due to sickness exceeded 4,000.
"Kokoda Trail" and "Kokoda Track" have been used interchangeably since the Second World War and the former was adopted by the Battles Nomenclature Committee as the official British Commonwealth battle honour in October 1957.