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 dispute originated in 1969 when the two countries negotiated to delimit the common border of their continental shelf. As the two countries could not agree on the soveignty of the two islands, the continental shelf border was left off the 1969 agreement between the two countries. Indonesia claimed that the islands were theirs by virtue of the fact that they were located south of 4° 10" North which it said formed the maritime border between it and Malaysia by virtue of a straight line extension of the land border which ended on the east coast Sebatik island. Malaysia however, claimed