It rises near Mount Barron and flows south then south-east through Lake Sumner Forest Park, reaching the Boyle River 40 kilometres (25 mi) west of Hanmer Springs.

The Doubtless River and Devilskin Stream are tributaries entering from the north.

[1] The New Zealand Department of Conservation maintains a tramping track alongside the river, with routes off to the north[2] and south.

[3] Backcountry huts are available for trampers near the junctions with the Devilskin Stream[4] and Doubtless River.

This article about a river in Canterbury, New Zealand is a stub.