The border was delineated in 1958 by the United Kingdom who then had sovereignty over the colony of Sarawak and was responsible for the external relations of the protectorate of Brunei. An immigration post was built in the 1960s to control the movement of goods and people between Miri and points west in Sarawak with Brunei. It has been continually upgraded since then, with the latest upgrade being made just prior to the opening of the ASEAN Bridge across the Baram River.