Cape Gloucester is a headland that sits on the northern peninsula at the west end of the island of New Britain, which lies to the northeast of mainland New Guinea. It is roughly opposite to the Huon Peninsula, from which it is separated by Rooke Island with the intervening sea lane divided into the Vitiaz and Dampier Straits. At the time of the battle it was part of the Territory of New Guinea. It is west of Rabaul, and northeast of Port Moresby. The peninsula on which Cape Gloucester sits consists of a rough semi-circular coast, extending from Lagoon Point in the west to Borgen Bay in the east. At the base of the peninsula is Mount Talawe, a extinct volcano, which runs laterally east to west. Southwest of Talawe, a semi-active volcano, Langila, rises , while further to the south, a second extinct volcano, Mount Tangi rises to . The area is densely vegetated with thick rainforest, sharp kunai grass and deep mangrove swamps. In 1943, there were only a few beaches suitable for landing operations and there were no roads around the coast along which troops and vehicles could quickly advance.