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
Brunei–Malaysia border goes a further 44 km to the Teraja Hills. From there, the border runs along the watershed between the Belait and Tutong rivers on one hand, and the Baram and Limbang rivers on the other hand. It then proceeds along the watershed of the Brunei and Limbang river basins, enters and runs along Sungai Mendaun, Sungai Melais and Sungai Menunggul (Menunggol) until its estuary at Brunei Bay. The land border between Malaysia and Brunei's Temburong District (which is separated from the other part of Brunei) starts at the estuary of the Pandaruan River and runs the entire length of the