The position of its source is uncertain, as it is formed from a large number of small burns; for example, one of these rises on the slopes of Cruach nam Mult, at grid reference NN165056 and an elevation of about 2,000 feet (600 m).

The river flows south-west until it reaches the head of a glacial valley near Strachur, Loch Fyne.

(For a short distance it forms the boundary of the Argyll Forest Park, which it soon enters.)

The river does not enter Loch Fyne, but instead turns south-east.

Before reaching Loch Eck, it passes near the tiny settlements of Balliemore and Invernoaden[1] and Glenbranter.