The Fitzroy River rises below Mount Vandyke in the
Cobboboonee National Park, near the western edge of the
Lower Glenelg National Park. The river flows east by south, through , then between the western edge of the
Tyrendarra lava flow and the Mount Clay escarpment, and thence across a coastal plain. The river is joined by two minor tributaries before reaching its
mouth and emptying into
Portland Bay in the
Great Australian Bight southeast of . The river descends over its
course. The river is traversed by the
Henty Highway at Heywood and the
Princes Highway at Tyrendarra. ==Etymology==