The river is a major water supply source for towns and cities in the lower Central Highlands region.

The river rises below Little Hampton near Lyonville in the Great Dividing Range and flows generally north, descending 33 metres (108 ft) over the Trentham Falls, and continuing to flow northward to the Upper Coliban, Lauriston and Malmsbury reservoirs.

Subsequently, it flows through Malmsbury, Metcalfe, Redesdale and Mintaro, and finally reaches its confluence with the Campaspe River within Lake Eppalock.

As the population of those cities grew a water supply system consisting of 70 kilometres (43 mi) of tunnels and aqueducts was constructed.

[5] The river is home to the platypus as well as eight native fish species, including the Macquarie perch.