East Malaysia is 50% bigger than Peninsular Malaysia at , comparable with South Dakota or Great Britain. East Malaysia contains the five highest mountains in Malaysia, the highest being Mount Kinabalu at 4095 m, which is also the highest mountain in Borneo and the 10th highest mountain peak in Southeast Asia. It also contains the two longest rivers in Malaysia – Rajang River and Kinabatangan River. Banggi Island in Sabah and Bruit Island in Sarawak are the two largest islands that are located entirely within Malaysia. The largest island is Borneo, which is shared with Indonesia and Brunei. The second largest island
Indonesia–Malaysia border Island. A stretch of the Indonesia–Malaysia border will run in between. This will effectively establish three Indonesia-Malaysia-Singapore tripoints in the area. The determination of boundaries to fill the various gaps and defining the various tripoints would require Indonesia-Malaysia-Singapore trilateral negotiations. Again, the only a continental shelf boundary has been agreed to in this segment of the maritime border between the two countries. The boundary begins at Point 21 with coordinates 109° 38'.8E 02° 05'.0N (109° 38' 48"E 02° 05'N) off Tanjung Datu at the western extremity of the Malaysia state of Sarawak. Incidentally, the Indonesian baseline at Tanjung Datu is