The Rejang (also known as Rajang) river, with 563km the longest river in Malaysia, penetrates deeply into the territory and serves a the major communications link between the coast and the interior areas. It originates in the Iran montains in Sarawak and flows into the South China sea. The upper part of Rejang river is also known as Batang Balui by the Orang Ulu, the native people of Sarawak. Towns on the Rejang river are Sibu, Kapit and Belaga. Speedboats do the trip from Belaga to Sibu in less than seven hours.