Southern Ladan Hills
The Southern Ladan Hills comprise a tract of some 25,000 ha of forested land in the interior of the Belait and Tutong Districts of Brunei, in north-western Borneo, which has been identified by BirdLife International as an Important Bird Area. Lying at an altitude of 100–300 m, it contains mixed dipterocarp, lower montane, tropical heath and limestone forest. It lies along the international border between Brunei and the Malaysian state of Sarawak, and is contiguous with the Gunung Mulu and Gunung Buda National Parks there.