Brunei–Malaysia border
The border between Brunei and Malaysia consist of a 481.3 km land border and substantial lengths of maritime borders stretching from the coastline of the two countries to the edge of the continental shelf in the South China Sea.
Except for its South China Sea coastline, Brunei is entirely surrounded by Malaysia's Sarawak state and the country only shares a land boundary with Malaysia. Brunei's unique shape where its territory consists of two non-contiguous portions results in its border with Malaysia being broken into two segments.
Brunei's 200 nautical mile continental shelfclaim makes it a claimant of a portion of the South China Sea that is subject to multiple overlapping claims by China, Taiwan and Vietnam. Malaysia is also a claimant in the area but a bilateral agreement with Brunei has solved the overlapping claims over Brunei's territorial waters.
From west to east, the Brunei–Malaysia border begins where the watershed of the Baram and Belait river basins meet the South China Sea at a point six nautical miles (11 km) east of Tanjung Baram with coordinates 4°35′20″N 114°5′00″E / 4.58889°N 114.08333°E. It then travels along the watershed of the two river basins for about 30 km to the Pagalayan Canal. It then 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 river to its source. It then runs along the watershed between the Temburong River on one hand, and the Limbang and then the Trusan rivers on the other until it reaches Brunei Bay. The northern terminus of this boundary is located at the mouth of the Sungai Bangau, based on the coordinated established by the Sarawak (Definition of Boundaries) Order in Council 1958.
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