Sourced by runoff from the
Bellenden Ker Range, the headwaters of the Mulgrave River rise as the east and west branches of the river below South Peak and west of , respectively. The two branches form their
confluence within the
Wooroonooran National Park and the
Wet Tropics World Heritage Area. The Mulgrave River flows generally north towards
Little Mulgrave, through the outskirts of , and continues through the
Goldsborough Valley. From Gordonvale, the river flows east by south and then south, eventually emptying into the
Coral Sea south at the southern extremity of the Yarrabah Hills range, where it meets the
Russell River. The
Trinity Inlet was once the river mouth of the Mulgrave River.
Volcanic activity that resulted in the rise of Green Hill in the Mulgrave Valley blocked the river from entering the sea near present-day Cairns. However, further research has shown river sediments above the basalt flows, suggesting that other factors, such as alluvial sediments, may have altered the river's course, possibly causing it to alternate between the two mouths over time. The river has a
catchment area of . From source to mouth, incorporating the east and west branches of the river, the river descends over a combined
course. The river is crossed by the
Bruce Highway south of Gordonvale via the
Desmond Trannore Bridge. == History ==