The
headwaters of the river are in the portion of Timor-Leste's central mountains ranging from, in the west, the westernmost parts of northern
Suco in
Barique Administrative Post, Manatuto municipality, to, in the east, the area surrounding the border between
Suco ,
Vemasse Administrative Post,
Baucau municipality, and
Suco ,
Ossu Administrative Post,
Viqueque municipality. The river itself rises in the area surrounding the border between
Suco Ossouala, Vemasse Administrative Post, Baucau municipality, and
Suco Liaruca, Ossu Administrative Post, Viqueque municipality. In its upper reaches, it is referred to in at least one source as the Mori River. Initially, it flows generally southwest, along or near the border between Baucau and Viqueque municipalities, to the
tripoint between those two municipalities and Manatuto. After running a short stretch further west, along the border between Manatuto and Viqueque municipalities, the river turns right and then flows generally north through Laleia Administrative Post, Manatuto. The first significant settlement it passes is Raimea,
Suco Cairui, on its left bank. Further north, it passes Samalai village, northern Cairui, also on its left bank, and later Laleia village, again on its left bank, where it flows under the adjacent Laleia Bridge, both being near the border between
Sucos Haturalan and Lifau, Laleia Administrative Post. A short additional distance north, it discharges into Wetar Strait, at the northern tip of the border between
Suco Lifau, Laleia Administrative Post, Manatuto, and
Suco Vemasse,
Vemasse Administrative Post, Baucau.): rises in far northern
Suco Liaruca, Ossu Administrative Post, Viqueque municipality, and takes a southwestern and then western route, becoming increasingly
meandering, until it enters the Laleia River near the border between Liaruca and
Suco Ossouala, Vemasse Administrative Post, Baucau municipality, close to the tripoint between
Sucos Ossouala, Liaruca, and a third
Suco, ,
Viqueque Administrative Post, Viqueque municipality; • Tutoli River: rises in
Suco Laline, Lacluta Administrative Post, Viqueque, and flows northwards to enter the Laleia River at the border between Laline and
Suco Ossouala, Vemasse Administrative Post, Baucau; main tributaries are the Buauomeca River (or Buacomeca River) and the Letatice River; • Abai River: rises in
Suco Laline, Lacluta Administrative Post, Viqueque, and flows northwards to enter the Laleia River at the border between Laline and
Suco Cairui, Laleia Administrative Post, Manatuto; main tributary is the Aihaet River; • Caleuc River: rises near the northernmost point of the border between
Suco Barique, Barique Administrative Post, Manatuto, and
Suco Laline, Lacluta Administrative Post, Viqueque, and then flows northwards along that border, followed by northeast and then east along the border between
Suco Cairui, Laleia Administrative Post, Manatuto, and
Suco Laline, until just before the tripoint between Baucau, Manatuo, and Viqueque municipalities, where it enters the Laleia River; main tributaries are the Ladada River and the Laburaque River (or Labaraque River); • Sorec River: rises in the northwestern corner of
Suco Barique, Barique Administrative Post, Manatuto as the Haeraun River; flows northwards into
Suco Cribas, Manatuto Administrative Post, Manatuto, where it becomes the Sorec River, passes over the , and begins to meander; crosses into
Suco , Manatuto Administrative Post, Manatuto, where it turns northeast, and then east, still meandering, until, soon after reaching and then taking a short run along the border between
Suco Aiteas and
Suco Haturalan, Laleia Administrative Post, Manatuto, it merges with the Bueana River (see below) at the tripoint between
Suco Aiteas,
Suco Haturalan, and
Suco Cairui, Laleia Administrative Post, Manatuto, to form the Baunoi River (see below); main tributary is the Lulic River; • Bueana River: rises near the centre of
Suco Cribas, Manatuto Administrative Post, Manatuto, as the Tuqueti River; flows generally northeasterly through that
suco, begins to meander, and changes its name to Bueana River; then, after reaching and taking a short run along the border between
Suco Cribas and
Suco Cairui, Laleia Administrative Post, Manatuto, and later a longer run along the border between
Suco Aiteas, Manatuto Administrative Post, Manatuto, and
Suco Cairui, it merges with the Sorec River (see above) at the tripoint between
Suco Aiteas,
Suco Cairui, and
Suco Haturalan, Laleia Administrative Post, Manatuto, to form the Baunoi River (see below); main tributary is the Boi River; • Baunoi River: flows from the confluence of the Sorec and Bueana rivers (see above), initially northeastwards along the border between
Sucos Haturalan and Cairui, Laleia Administrative Post, Manatuto, and then eastwards through
Suco Cairui to a short distance southwest of Raimea,
Suco Cairui, where it flows into the Laleia River; • Haui River: rises in eastern
Suco Cairui, Laleia Administrative Post, Manatuto, and flows generally northwards, until it enters the Laleia River just north of the border between
Sucos Cairui and Haturalan, Laleia Administrative Post, Manatuto; • Heuc River (or Heu River): rises in the northwest of
Suco Haturalan, LaleiaAdministrative Post, Manatuto, and flows generally northeastwards, until it enters the Laleia River at Laleia village, on the border between
Sucos Haturalan and Lifau, Laleia Administrative Post, Manatuto. ==Catchment==