The Bismarck Archipelago is a group of islands lying northeast of the island of New Guinea in Papua New Guinea. The ecoregion includes the lowland rain forests on New Britain, New Ireland, and nearby smaller islands, including Umboi, Long Island, and Karkar, near the New Guinea coast west of New Britain. The islands north of New Ireland, including New Hanover (Lavongai), the Saint Matthias Group, Tabar Group, Lihir Group, Tanga Islands, and Feni Islands, are also part of the ecoregion.