The Werribee River is a perennial river of the Port Phillip catchment that is located on the expansive lowland plain southwest of Melbourne, Victoria, Australia. The headwaters of a tributary, the Lerderderg River, are north of Ballan near Daylesford and it flows across the basalt plain, through the suburb of Werribee to enter Port Phillip. A linear park follows the Werribee River along much of its course. In total the Werribee River completes a journey of approximately 110 kilometres (68 mi).