Indonesia–Malaysia border Indonesia–Malaysia border The border between the Southeast Asian countries of Indonesia and Malaysia consist of both a land border separating the two countries' territories on the island of Borneo as well as maritime boundaries along the length of the Straits of Malacca, in the South China Sea and in the Celebes Sea. The land boundary has a length of 2,019.5 km and stretches from Tanjung Datu at the northwestern corner of Borneo, through the highlands of the Borneo hinterland, to the Gulf of Sebatik and the Celebes Sea in the eastern side of the island. The boundary separates the Indonesian
Geography of Malaysia districts. There are separate subdivisions for electoral districts for polling purposes. International borders between Malaysia and Indonesia, Thailand, Singapore and Brunei are defined mostly by geological features such as the Perlis River and Golok River between Malaysia and Thailand; Straits of Johor between Malaysia and Singapore; and Pagalayan Canal between Malaysia and Brunei. However, borders that extends to the seas are defined by agreements such as Straits Settlement and Johore Territorial Waters Agreement of 1927 which defines Malaysia and Singapore water borders. Malaysia's land borders are well established. The border with Thailand was established in 1909 when Siam ceded Kedah,